CCE Identifiers in Guide to the Secure Configuration of SUSE Linux Enterprise Micro 5


Mapping Rule Title Description Rationale
CCE-93601-3 The Installed Operating System Is Vendor Supported The installed operating system must be maintained by a vendor. SUSE Linux Enterprise is supported by SUSE. As the SUSE Linux Enterprise vendor, SUSE is responsible for providing security patches. An operating system is considered "supported" if the vendor continues to provide security patches for the product. With an unsupported release, it will not be possible to resolve any security issue discovered in the system software.
CCE-93602-1 Ensure auditd Collects Information on the Use of Privileged Commands - passwd At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93603-9 Ensure auditd Collects Information on the Use of Privileged Commands - gpasswd At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93604-7 Ensure auditd Collects Information on the Use of Privileged Commands - newgrp At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93605-4 Ensure auditd Collects Information on the Use of Privileged Commands - chsh At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93606-2 Ensure auditd Collects Information on the Use of Privileged Commands - unix_chkpwd At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93607-0 Ensure auditd Collects Information on the Use of Privileged Commands - chage At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93608-8 Ensure auditd Collects Information on the Use of Privileged Commands - crontab At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93609-6 Ensure auditd Collects Information on the Use of Privileged Commands - sudoedit At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93610-4 Ensure auditd Collects Information on the Use of Privileged Commands - chfn At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/chfn -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/chfn -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter).
CCE-93611-2 Record Any Attempts to Run ssh-agent At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/ssh-agent -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/ssh-agent -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter).
CCE-93612-0 Ensure auditd Collects Information on the Use of Privileged Commands - insmod At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /sbin/insmod -p x -k modules
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93613-8 Ensure auditd Collects Information on the Use of Privileged Commands - rmmod At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /sbin/rmmod -p x -k modules
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93614-6 Ensure auditd Collects Information on the Use of Privileged Commands - modprobe At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /sbin/modprobe -p x -k modules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-w /sbin/modprobe -p x -k modules
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93615-3 Ensure auditd Collects Information on the Use of Privileged Commands - kmod At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/kmod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/kmod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter).
CCE-93616-1 Record Any Attempts to Run chmod At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/chmod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/chmod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter).
CCE-93617-9 Record Any Attempts to Run setfacl At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter).
CCE-93618-7 Record Any Attempts to Run chacl At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter).
CCE-93619-5 Record Any Attempts to Run chcon At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93620-3 Record Any Attempts to Run rm At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/rm -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/rm -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter).
CCE-93621-1 Ensure auditd Collects Information on the Use of Privileged Commands - usermod At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93622-9 Ensure auditd Collects Information on the Use of Privileged Commands - pam_timestamp_check At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93623-7 Ensure auditd Collects Information on the Use of Privileged Commands - su At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93624-5 Ensure auditd Collects Information on the Use of Privileged Commands - sudo At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-93625-2 Restrict Access to Kernel Message Buffer To set the runtime status of the kernel.dmesg_restrict kernel parameter, run the following command:
$ sudo sysctl -w kernel.dmesg_restrict=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.dmesg_restrict = 1
Unprivileged access to the kernel syslog can expose sensitive kernel address information.
CCE-93626-0 Enable Kernel Parameter to Use TCP Syncookies on Network Interfaces To set the runtime status of the net.ipv4.tcp_syncookies kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.tcp_syncookies=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.tcp_syncookies = 1
A TCP SYN flood attack can cause a denial of service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies can be used to track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This feature is activated when a flood condition is detected, and enables the system to continue servicing valid connection requests.
CCE-93627-8 Restrict Exposed Kernel Pointer Addresses Access To set the runtime status of the kernel.kptr_restrict kernel parameter, run the following command:
$ sudo sysctl -w kernel.kptr_restrict=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.kptr_restrict = 1
Exposing kernel pointers (through procfs or seq_printf()) exposes kernel writeable structures which may contain functions pointers. If a write vulnerability occurs in the kernel, allowing write access to any of this structure, the kernel can be compromised. This option disallow any program without the CAP_SYSLOG capability to get the addresses of kernel pointers by replacing them with 0.
CCE-93628-6 Enable Randomized Layout of Virtual Address Space To set the runtime status of the kernel.randomize_va_space kernel parameter, run the following command:
$ sudo sysctl -w kernel.randomize_va_space=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.randomize_va_space = 2
Address space layout randomization (ASLR) makes it more difficult for an attacker to predict the location of attack code they have introduced into a process's address space during an attempt at exploitation. Additionally, ASLR makes it more difficult for an attacker to know the location of existing code in order to re-purpose it using return oriented programming (ROP) techniques.
CCE-93629-4 Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv4 Interfaces To set the runtime status of the net.ipv4.conf.all.accept_source_route kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.accept_source_route = 0
Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv4 forwarding is enabled and the system is functioning as a router.

Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.
CCE-93630-2 Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv6 Interfaces To set the runtime status of the net.ipv6.conf.all.accept_source_route kernel parameter, run the following command:
$ sudo sysctl -w net.ipv6.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.all.accept_source_route = 0
Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router.

Accepting source-routed packets in the IPv6 protocol has few legitimate uses. It should be disabled unless it is absolutely required.
CCE-93631-0 Disable Kernel Parameter for Accepting Source-Routed Packets on IPv4 Interfaces by Default To set the runtime status of the net.ipv4.conf.default.accept_source_route kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.accept_source_route = 0
Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures.
Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required, such as when IPv4 forwarding is enabled and the system is legitimately functioning as a router.
CCE-93632-8 Disable Kernel Parameter for Accepting Source-Routed Packets on IPv6 Interfaces by Default To set the runtime status of the net.ipv6.conf.default.accept_source_route kernel parameter, run the following command:
$ sudo sysctl -w net.ipv6.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.default.accept_source_route = 0
Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router. Accepting source-routed packets in the IPv6 protocol has few legitimate uses. It should be disabled unless it is absolutely required.
CCE-93633-6 Disable Accepting ICMP Redirects for All IPv4 Interfaces To set the runtime status of the net.ipv4.conf.all.accept_redirects kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.accept_redirects = 0
ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless absolutely required."
CCE-93634-4 Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv4 Interfaces To set the runtime status of the net.ipv4.conf.default.accept_redirects kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.accept_redirects = 0
ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless absolutely required.
CCE-93635-1 Disable Accepting ICMP Redirects for All IPv6 Interfaces To set the runtime status of the net.ipv6.conf.all.accept_redirects kernel parameter, run the following command:
$ sudo sysctl -w net.ipv6.conf.all.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.all.accept_redirects = 0
An illicit ICMP redirect message could result in a man-in-the-middle attack.
CCE-93636-9 Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv6 Interfaces To set the runtime status of the net.ipv6.conf.default.accept_redirects kernel parameter, run the following command:
$ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.default.accept_redirects = 0
An illicit ICMP redirect message could result in a man-in-the-middle attack.
CCE-93637-7 Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces by Default To set the runtime status of the net.ipv4.conf.default.send_redirects kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.default.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.send_redirects = 0
ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers.
CCE-93638-5 Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces To set the runtime status of the net.ipv4.conf.all.send_redirects kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.all.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.send_redirects = 0
ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers.
CCE-93639-3 Disable Kernel Parameter for IP Forwarding on IPv4 Interfaces To set the runtime status of the net.ipv4.ip_forward kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.ip_forward=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.ip_forward = 0
Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this capability is used when not required, system network information may be unnecessarily transmitted across the network.
CCE-93640-1 Disable Kernel Parameter for IPv6 Forwarding To set the runtime status of the net.ipv6.conf.all.forwarding kernel parameter, run the following command:
$ sudo sysctl -w net.ipv6.conf.all.forwarding=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.all.forwarding = 0
IP forwarding permits the kernel to forward packets from one network interface to another. The ability to forward packets between two networks is only appropriate for systems acting as routers.
CCE-93641-9 Disable Kernel Parameter for IPv6 Forwarding by default To set the runtime status of the net.ipv6.conf.default.forwarding kernel parameter, run the following command:
$ sudo sysctl -w net.ipv6.conf.default.forwarding=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.default.forwarding = 0
IP forwarding permits the kernel to forward packets from one network interface to another. The ability to forward packets between two networks is only appropriate for systems acting as routers.
CCE-93642-7 Enable SSH Warning Banner To enable the warning banner and ensure it is consistent across the system, add or correct the following line in /etc/ssh/sshd_config:
Banner /etc/issue
Another section contains information on how to create an appropriate system-wide warning banner.
The warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers. Alternatively, systems whose ownership should not be obvious should ensure usage of a banner that does not provide easy attribution.
CCE-93643-5 Set SSH Daemon LogLevel to VERBOSE The VERBOSE parameter configures the SSH daemon to record login and logout activity. To specify the log level in SSH, add or correct the following line in /etc/ssh/sshd_config:
LogLevel VERBOSE
SSH provides several logging levels with varying amounts of verbosity. DEBUG is specifically not recommended other than strictly for debugging SSH communications since it provides so much data that it is difficult to identify important security information. INFO or VERBOSE level is the basic level that only records login activity of SSH users. In many situations, such as Incident Response, it is important to determine when a particular user was active on a system. The logout record can eliminate those users who disconnected, which helps narrow the field.
CCE-93644-3 Disable SSH Root Login The root user should never be allowed to login to a system directly over a network. To disable root login via SSH, add or correct the following line in /etc/ssh/sshd_config:
PermitRootLogin no
Even though the communications channel may be encrypted, an additional layer of security is gained by extending the policy of not logging directly on as root. In addition, logging in with a user-specific account provides individual accountability of actions performed on the system and also helps to minimize direct attack attempts on root's password.
CCE-93645-0 Enable SSH Print Last Log Ensure that SSH will display the date and time of the last successful account logon.
The default SSH configuration enables print of the date and time of the last login. The appropriate configuration is used if no value is set for PrintLastLog.
To explicitly enable LastLog in SSH, add or correct the following line in /etc/ssh/sshd_config:
PrintLastLog yes
Providing users feedback on when account accesses last occurred facilitates user recognition and reporting of unauthorized account use.
CCE-93646-8 Disable SSH Support for User Known Hosts SSH can allow system users to connect to systems if a cache of the remote systems public keys is available. This should be disabled.

To ensure this behavior is disabled, add or correct the following line in /etc/ssh/sshd_config:
IgnoreUserKnownHosts yes
Configuring this setting for the SSH daemon provides additional assurance that remote login via SSH will require a password, even in the event of misconfiguration elsewhere.
CCE-93647-6 Enable Use of Strict Mode Checking SSHs StrictModes option checks file and ownership permissions in the user's home directory .ssh folder before accepting login. If world- writable permissions are found, logon is rejected.
The default SSH configuration has StrictModes enabled. The appropriate configuration is used if no value is set for StrictModes.
To explicitly enable StrictModes in SSH, add or correct the following line in /etc/ssh/sshd_config:
StrictModes yes
If other users have access to modify user-specific SSH configuration files, they may be able to log into the system as another user.
CCE-93648-4 Disable X11 Forwarding The X11Forwarding parameter provides the ability to tunnel X11 traffic through the connection to enable remote graphic connections. SSH has the capability to encrypt remote X11 connections when SSH's X11Forwarding option is enabled.
The default SSH configuration disables X11Forwarding. The appropriate configuration is used if no value is set for X11Forwarding.
To explicitly disable X11 Forwarding, add or correct the following line in /etc/ssh/sshd_config:
X11Forwarding no
Disable X11 forwarding unless there is an operational requirement to use X11 applications directly. There is a small risk that the remote X11 servers of users who are logged in via SSH with X11 forwarding could be compromised by other users on the X11 server. Note that even if X11 forwarding is disabled, users can always install their own forwarders.
CCE-93649-2 Do Not Allow SSH Environment Options Ensure that users are not able to override environment variables of the SSH daemon.
The default SSH configuration disables environment processing. The appropriate configuration is used if no value is set for PermitUserEnvironment.
To explicitly disable Environment options, add or correct the following /etc/ssh/sshd_config:
PermitUserEnvironment no
SSH environment options potentially allow users to bypass access restriction in some configurations.
CCE-93650-0 Disable SSH Access via Empty Passwords Disallow SSH login with empty passwords. The default SSH configuration disables logins with empty passwords. The appropriate configuration is used if no value is set for PermitEmptyPasswords.
To explicitly disallow SSH login from accounts with empty passwords, add or correct the following line in /etc/ssh/sshd_config:
PermitEmptyPasswords no
Any accounts with empty passwords should be disabled immediately, and PAM configuration should prevent users from being able to assign themselves empty passwords.
Configuring this setting for the SSH daemon provides additional assurance that remote login via SSH will require a password, even in the event of misconfiguration elsewhere.
CCE-93651-8 Record Events that Modify the System's Discretionary Access Controls - fremovexattr At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93652-6 Record Events that Modify the System's Discretionary Access Controls - lchown At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93653-4 Record Events that Modify the System's Discretionary Access Controls - fchmod At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93654-2 Ensure auditd Collects Information on Exporting to Media (successful) At a minimum, the audit system should collect media exportation events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export
The unauthorized exportation of data to external media could result in an information leak where classified information, Privacy Act information, and intellectual property could be lost. An audit trail should be created each time a filesystem is mounted to help identify and guard against information loss.
CCE-93655-9 Record Events that Modify the System's Discretionary Access Controls - umount2 At a minimum, the audit system should collect file system umount2 changes. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93656-7 Record Events that Modify User/Group Information - /etc/passwd If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.
CCE-93657-5 Record Events that Modify User/Group Information - /etc/group If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/group -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /etc/group -p wa -k audit_rules_usergroup_modification
In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.
CCE-93658-3 Record Events that Modify User/Group Information - /etc/shadow If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.
CCE-93659-1 Record Events that Modify User/Group Information - /etc/security/opasswd If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.
CCE-93660-9 Verify permissions of log files Any operating system providing too much information in error messages risks compromising the data and security of the structure, and content of error messages needs to be carefully considered by the organization. Organizations carefully consider the structure/content of error messages. The extent to which information systems are able to identify and handle error conditions is guided by organizational policy and operational requirements. Information that could be exploited by adversaries includes, for example, erroneous logon attempts with passwords entered by mistake as the username, mission/business information that can be derived from (if not stated explicitly by) information recorded, and personal information, such as account numbers, social security numbers, and credit card numbers. The SUSE Linux Enterprise Micro 5 must generate error messages that provide information necessary for corrective actions without revealing information that could be exploited by adversaries.
CCE-93663-3 Verify Permissions on SSH Server Public *.pub Key Files To properly set the permissions of /etc/ssh/*.pub, run the command:
$ sudo chmod 0644 /etc/ssh/*.pub
If a public host key file is modified by an unauthorized user, the SSH service may be compromised.
CCE-93664-1 Record Attempts to Alter Logon and Logout Events - tallylog The audit system already collects login information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /var/log/tallylog -p wa -k logins
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /var/log/tallylog -p wa -k logins
Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
CCE-93665-8 Record Attempts to Alter Logon and Logout Events - lastlog The audit system already collects login information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /var/log/lastlog -p wa -k logins
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /var/log/lastlog -p wa -k logins
Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
CCE-93666-6 Record Unsuccessful Access Attempts to Files - open At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
CCE-93667-4 Record Unsuccessful Delete Attempts to Files - rename The audit system should collect unsuccessful file deletion attempts for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file.
-a always,exit -F arch=b32 -S rename -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b32 -S rename -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S rename -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b64 -S rename -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
Unsuccessful attempts to delete files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
CCE-93671-6 Limit the Number of Concurrent Login Sessions Allowed Per User Limiting the number of allowed users and sessions per user can limit risks related to Denial of Service attacks. This addresses concurrent sessions for a single account and does not address concurrent sessions by a single user via multiple accounts. To set the number of concurrent sessions per user add the following line in /etc/security/limits.conf or a file under /etc/security/limits.d/:
* hard maxlogins 1
Limiting simultaneous user logins can insulate the system from denial of service problems caused by excessive logins. Automated login processes operating improperly or maliciously may result in an exceptional number of simultaneous login sessions.
CCE-93672-4 Use Only FIPS 140-2 Validated Ciphers Limit the ciphers to those algorithms which are FIPS-approved. The following line in /etc/ssh/sshd_config demonstrates use of FIPS-approved ciphers:
Ciphers aes256-ctr,aes192-ctr,aes128-ctr
This rule ensures that there are configured ciphers mentioned above (or their subset), keeping the given order of algorithms.
Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied upon to provide confidentiality or integrity, and system data may be compromised.
Operating systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules.
FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets industry and government requirements. For government systems, this allows Security Levels 1, 2, 3, or 4 for use on SUSE Linux Enterprise Micro 5.
CCE-93673-2 Use Only FIPS 140-2 Validated Ciphers Limit the ciphers to those algorithms which are FIPS-approved. Counter (CTR) mode is also preferred over cipher-block chaining (CBC) mode. The following line in /etc/ssh/sshd_config demonstrates use of FIPS-approved ciphers:
Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
The man page sshd_config(5) contains a list of supported ciphers. The rule is parametrized to use the following ciphers: aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se.
Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied upon to provide confidentiality or integrity, and system data may be compromised.
Operating systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules.
FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets industry and government requirements. For government systems, this allows Security Levels 1, 2, 3, or 4 for use on SUSE Linux Enterprise Micro 5.
CCE-93674-0 Ensure auditd Collects System Administrator Actions If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/sudoers -p wa -k actions
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /etc/sudoers -p wa -k actions
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/sudoers.d/ -p wa -k actions
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /etc/sudoers.d/ -p wa -k actions
The actions taken by system administrators should be audited to keep a record of what was executed on the system, as well as, for accountability purposes.
CCE-93675-7 Ensure auditd Collects Information on Kernel Module Unloading - delete_module To capture kernel module loading and unloading events, use the following line, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S delete_module -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the line to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the line to file /etc/audit/audit.rules.
The removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.
CCE-93676-5 Ensure auditd Collects Information on Kernel Module Loading and Unloading - finit_module To capture kernel module loading and unloading events, use the following line, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S finit_module -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the line to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the line to file /etc/audit/audit.rules.
The addition/removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.
CCE-93677-3 Configure auditd mail_acct Action on Low Disk Space The auditd service can be configured to send email to a designated account in certain situations. Add or correct the following line in /etc/audit/auditd.conf to ensure that administrators are notified via email for those situations:
action_mail_acct = root
Email sent to the root account is typically aliased to the administrators of the system, who can take appropriate action.
CCE-93678-1 Configure System to Forward All Mail For The Root Account Make sure that mails delivered to root user are forwarded to a monitored email address. Make sure that the address change_me@localhost is a valid email address reachable from the system in question. Use the following command to configure the alias:
$ sudo echo "root: change_me@localhost" >> /etc/aliases
$ sudo newaliases
A number of system services utilize email messages sent to the root user to notify system administrators of active or impending issues. These messages must be forwarded to at least one monitored email address.
CCE-93679-9 Configure auditd Disk Full Action when Disk Space Is Full The auditd service can be configured to take an action when disk space is running low but prior to running out of space completely. Edit the file /etc/audit/auditd.conf. Add or modify the following line, substituting ACTION appropriately:
disk_full_action = ACTION
Set this value to single to cause the system to switch to single-user mode for corrective action. Acceptable values also include syslog, exec, single, and halt For certain systems, the need for availability outweighs the need to log all actions, and a different setting should be determined. Details regarding all possible values for ACTION are described in the auditd.conf man page.
Taking appropriate action in case of a filled audit storage volume will minimize the possibility of losing audit records.
CCE-93680-7 Configure Smart Card Certificate Authority Validation Configure the operating system to do certificate status checking for PKI authentication. Modify all of the cert_policy lines in /etc/pam_pkcs11/pam_pkcs11.conf to include ca like so:
cert_policy = ca, ocsp_on, signature;
Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device.

Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards or similar secure authentication devices issued by an organization or identity provider.
CCE-93681-5 Set PAM Password Hashing Algorithm - system-auth The PAM system service can be configured to only store encrypted representations of passwords. In "/etc/pam.d/common-password", the password section of the file controls which PAM modules to execute during a password change. Set the pam_unix.so module in the password section to include the option sha512 and no other hashing algorithms as shown below:
password    required    pam_unix.so sha512 other arguments...

This will help ensure that new passwords for local users will be stored using the sha512 algorithm.
Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Passwords that are encrypted with a weak algorithm are no more protected than if they are kept in plain text.

This setting ensures user and group account administration utilities are configured to store only encrypted representations of passwords. Additionally, the crypt_style configuration option in /etc/libuser.conf ensures the use of a strong hashing algorithm that makes password cracking attacks more difficult.
CCE-93682-3 Set Password Hashing Rounds in /etc/login.defs In /etc/login.defs, ensure SHA_CRYPT_MIN_ROUNDS and SHA_CRYPT_MAX_ROUNDS has the minimum value of 5000. For example:
SHA_CRYPT_MIN_ROUNDS 5000
SHA_CRYPT_MAX_ROUNDS 5000
Notice that if neither are set, they already have the default value of 5000. If either is set, they must have the minimum value of 5000.
Passwords need to be protected at all times, and hashing is the standard method for protecting passwords. If passwords are not hashed, they can be plainly read (i.e., clear text) and easily compromised. Passwords that are hashed with a weak algorithm are no more protected than if they are kept in plain text.

Using more hashing rounds makes password cracking attacks more difficult.
CCE-93683-1 Set Password Minimum Age To specify password minimum age for new accounts, edit the file /etc/login.defs and add or correct the following line:
PASS_MIN_DAYS 7
A value of 1 day is considered sufficient for many environments. The profile requirement is 7.
Enforcing a minimum password lifetime helps to prevent repeated password changes to defeat the password reuse or history enforcement requirement. If users are allowed to immediately and continually change their password, then the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse.

Setting the minimum password age protects against users cycling back to a favorite password after satisfying the password reuse requirement.
CCE-93684-9 Set Existing Passwords Minimum Age Configure non-compliant accounts to enforce a 24 hours/1 day minimum password lifetime by running the following command:
$ sudo chage -m 1 USER
Enforcing a minimum password lifetime helps to prevent repeated password changes to defeat the password reuse or history enforcement requirement. If users are allowed to immediately and continually change their password, the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse.
CCE-93685-6 Set Password Maximum Age To specify password maximum age for new accounts, edit the file /etc/login.defs and add or correct the following line:
PASS_MAX_DAYS 60
The profile requirement is 60.
Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. If the operating system does not limit the lifetime of passwords and force users to change their passwords, there is the risk that the operating system passwords could be compromised.

Setting the password maximum age ensures users are required to periodically change their passwords. Requiring shorter password lifetimes increases the risk of users writing down the password in a convenient location subject to physical compromise.
CCE-93686-4 Set Existing Passwords Maximum Age Configure non-compliant accounts to enforce a 60-day maximum password lifetime restriction by running the following command:
$ sudo passwd -x 60 USER
Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. If the operating system does not limit the lifetime of passwords and force users to change their passwords, there is the risk that the operating system passwords could be compromised.
CCE-93687-2 Verify Permissions and Ownership of Old Passwords File To properly set the owner of /etc/security/opasswd, run the command:
$ sudo chown root /etc/security/opasswd 
To properly set the group owner of /etc/security/opasswd, run the command:
$ sudo chgrp root /etc/security/opasswd
To properly set the permissions of /etc/security/opasswd, run the command:
$ sudo chmod 0600 /etc/security/opasswd
The /etc/security/opasswd file stores old passwords to prevent password reuse. Protection of this file is critical for system security.
CCE-93688-0 Set Account Expiration Following Inactivity To specify the number of days after a password expires (which signifies inactivity) until an account is permanently disabled, add or correct the following line in /etc/default/useradd:
INACTIVE=35
If a password is currently on the verge of expiration, then 35 day(s) remain(s) until the account is automatically disabled. However, if the password will not expire for another 60 days, then 60 days plus 35 day(s) could elapse until the account would be automatically disabled. See the useradd man page for more information.
Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system. Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials. Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained.
CCE-93689-8 Set Password Hashing Algorithm in /etc/login.defs In /etc/login.defs, add or update the following line to ensure the system will use SHA512 as the hashing algorithm:
ENCRYPT_METHOD SHA512
Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Passwords that are encrypted with a weak algorithm are no more protected than if they are kept in plain text.

Using a stronger hashing algorithm makes password cracking attacks more difficult.
CCE-93690-6 Use Only FIPS 140-2 Validated MACs Limit the MACs to those hash algorithms which are FIPS-approved. The following line in /etc/ssh/sshd_config demonstrates use of FIPS-approved MACs:
MACs hmac-sha2-512,hmac-sha2-256
This rule ensures that there are configured MACs mentioned above (or their subset), keeping the given order of algorithms.
FIPS-approved cryptographic hash functions are required to be used. The only SSHv2 hash algorithms meeting this requirement is SHA2.
CCE-93691-4 Use Only FIPS 140-2 Validated MACs Limit the MACs to those hash algorithms which are FIPS-approved. The following line in /etc/ssh/sshd_config demonstrates use of FIPS-approved MACs:
MACs hmac-sha2-512,hmac-sha2-256
The man page sshd_config(5) contains a list of supported MACs. The rule is parametrized to use the following MACs: hmac-sha2-512,hmac-sha2-256,hmac-sha1,hmac-sha1-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com.
FIPS-approved cryptographic hash functions are required to be used. The only SSHv2 hash algorithms meeting this requirement is SHA2.
CCE-93692-2 Set SSH Client Alive Interval SSH allows administrators to set a network responsiveness timeout interval. After this interval has passed, the unresponsive client will be automatically logged out.

To set this timeout interval, edit the following line in /etc/ssh/sshd_config as follows:
ClientAliveInterval 300


The timeout interval is given in seconds. For example, have a timeout of 10 minutes, set interval to 600.

If a shorter timeout has already been set for the login shell, that value will preempt any SSH setting made in /etc/ssh/sshd_config. Keep in mind that some processes may stop SSH from correctly detecting that the user is idle.
Terminating an idle ssh session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been let unattended.
CCE-93693-0 Verify that All World-Writable Directories Have Sticky Bits Set When the so-called 'sticky bit' is set on a directory, only the owner of a given file may remove that file from the directory. Without the sticky bit, any user with write access to a directory may remove any file in the directory. Setting the sticky bit prevents users from removing each other's files. In cases where there is no reason for a directory to be world-writable, a better solution is to remove that permission rather than to set the sticky bit. However, if a directory is used by a particular application, consult that application's documentation instead of blindly changing modes.
To set the sticky bit on a world-writable directory DIR, run the following command:
$ sudo chmod +t DIR
Failing to set the sticky bit on public directories allows unauthorized users to delete files in the directory structure.

The only authorized public directories are those temporary directories supplied with the system, or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system, by users for temporary file storage (such as /tmp), and for directories requiring global read/write access.
CCE-93694-8 Set SSH Client Alive Count Max The SSH server sends at most ClientAliveCountMax messages during a SSH session and waits for a response from the SSH client. The option ClientAliveInterval configures timeout after each ClientAliveCountMax message. If the SSH server does not receive a response from the client, then the connection is considered unresponsive and terminated. For SSH earlier than v8.2, a ClientAliveCountMax value of 0 causes a timeout precisely when the ClientAliveInterval is set. Starting with v8.2, a value of 0 disables the timeout functionality completely. If the option is set to a number greater than 0, then the session will be disconnected after ClientAliveInterval * ClientAliveCountMax seconds without receiving a keep alive message. This ensures a user login will be terminated as soon as the ClientAliveInterval is reached.
CCE-93695-5 Verify that local /var/log/messages is not world-readable Files containing sensitive information should be protected by restrictive permissions. Most of the time, there is no need that these files need to be read by any non-root user To properly set the permissions of /var/log/messages, run the command:
$ sudo chmod 0640 /var/log/messages
Check that "permissions.local" file contains the correct permissions rules with the following command:
# grep -i messages /etc/permissions.local

/var/log/messages root:root 640
The /var/log/messages file contains system error messages. Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the SUSE operating system or platform. Additionally, Personally Identifiable Information (PII) and operational information must not be revealed through error messages to unauthorized personnel or their designated representatives.
CCE-93696-3 Use Only FIPS 140-2 Validated Key Exchange Algorithms Limit the key exchange algorithms to those which are FIPS-approved. Add or modify the following line in /etc/ssh/sshd_config
KexAlgorithms ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256
This rule ensures that only the key exchange algorithms mentioned above (or their subset) are configured for use, keeping the given order of algorithms.
FIPS-approved key exchange algorithms are required to be used. The system will attempt to use the first algorithm presented by the client that matches the server list. Listing the values "strongest to weakest" is a method to ensure the use of the strongest algorithm available to secure the SSH connection.
CCE-93697-1 Verify Permissions of Local Logs of audit Tools The SUSE operating system audit tools must have the proper permissions configured to protect against unauthorized access. Check that "permissions.local" file contains the correct permissions rules with the following command:
grep "^/usr/sbin/au" /etc/permissions.local

/usr/sbin/audispd root:root 0750
/usr/sbin/auditctl root:root 0750
/usr/sbin/auditd root:root 0750
/usr/sbin/ausearch root:root 0755
/usr/sbin/aureport root:root 0755
/usr/sbin/autrace root:root 0750
/usr/sbin/augenrules root:root 0750
Audit tools include but are not limited to vendor-provided and open-source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators.
Protecting audit information also includes identifying and protecting the tools used to view and manipulate log data. Therefore, protecting audit tools is necessary to prevent unauthorized operation on audit information. SUSE operating systems providing tools to interface with audit information will leverage user permissions and roles identifying the user accessing the tools and the corresponding rights the user enjoys to make access decisions regarding the access to audit tools.
CCE-93698-9 Verify that System Executables Have Restrictive Permissions System executables are stored in the following directories by default:
/bin
/sbin
/usr/bin
/usr/libexec
/usr/local/bin
/usr/local/sbin
/usr/sbin
All files in these directories should not be group-writable or world-writable. If any file FILE in these directories is found to be group-writable or world-writable, correct its permission with the following command:
$ sudo chmod go-w FILE
System binaries are executed by privileged users, as well as system services, and restrictive permissions are necessary to ensure execution of these programs cannot be co-opted.
CCE-93699-7 Verify that System Executables Have Root Ownership System executables are stored in the following directories by default:
/bin
/sbin
/usr/bin
/usr/libexec
/usr/local/bin
/usr/local/sbin
/usr/sbin
All files in these directories should be owned by the root user. If any file FILE in these directories is found to be owned by a user other than root, correct its ownership with the following command:
$ sudo chown root FILE
System binaries are executed by privileged users as well as system services, and restrictive permissions are necessary to ensure that their execution of these programs cannot be co-opted.
CCE-93700-3 Verify that system commands directories have root ownership System commands are stored in the following directories by default:
/bin 
/sbin 
/usr/bin 
/usr/sbin 
/usr/local/bin 
/usr/local/sbin
All these directories should be owned by the root user. If any system command directory is not owned by a user other than root correct its ownership with the following command:
$ sudo chown root DIR
If the operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
CCE-93701-1 Verify that system commands files are group owned by root or a system account System commands files are stored in the following directories by default:
/bin
/sbin
/usr/bin
/usr/sbin
/usr/local/bin
/usr/local/sbin
All files in these directories should be owned by the root group, or a system account. If the directory, or any file in these directories, is found to be owned by a group other than root or a a system account correct its ownership with the following command:
$ sudo chgrp root FILE
If the operating system allows any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
CCE-93702-9 Verify that system commands directories have root as a group owner System commands are stored in the following directories: by default:
/bin 
/sbin 
/usr/bin 
/usr/sbin 
/usr/local/bin 
/usr/local/sbin
All these directories should have root user as a group owner. If any system command directory is not group owned by a user other than root correct its ownership with the following command:
$ sudo chgrp root DIR
If the operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
CCE-93703-7 Configure AIDE to Verify the Audit Tools The operating system file integrity tool must be configured to protect the integrity of the audit tools. Protecting the integrity of the tools used for auditing purposes is a critical step toward ensuring the integrity of audit information. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity. Audit tools include but are not limited to vendor-provided and open-source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators. It is not uncommon for attackers to replace the audit tools or inject code into the existing tools to provide the capability to hide or erase system activity from the audit logs. To address this risk, audit tools must be cryptographically signed to provide the capability to identify when the audit tools have been modified, manipulated, or replaced. An example is a checksum hash of the file or files.
CCE-93704-5 Deactivate Wireless Network Interfaces Deactivating wireless network interfaces should prevent normal usage of the wireless capability.

Configure the system to disable wireless network interfaces by issuing the following command for every active <WIFI-INTERFACE> in the system:
$ sudo wicked ifdown <WIFI-INTERFACE>
Also remove the configuration files for every wifi adapter from /etc/wicked/ifconfig/<WIFI-INTERFACE>.xml to prevent future connections.
The use of wireless networking can introduce many different attack vectors into the organization's network. Common attack vectors such as malicious association and ad hoc networks will allow an attacker to spoof a wireless access point (AP), allowing validated systems to connect to the malicious AP and enabling the attacker to monitor and record network traffic. These malicious APs can also serve to create a man-in-the-middle attack or be used to create a denial of service to valid network resources.
CCE-93705-2 Record Events When Privileged Executables Are Run Verify the system generates an audit record when privileged functions are executed. If audit is using the "auditctl" tool to load the rules, run the following command:
$ sudo grep execve /etc/audit/audit.rules
If audit is using the "augenrules" tool to load the rules, run the following command:
$ sudo grep -r execve /etc/audit/rules.d
-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k setuid
-a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k setuid
-a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k setgid
-a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k setgid
If both the "b32" and "b64" audit rules for "SUID" files are not defined, this is a finding. If both the "b32" and "b64" audit rules for "SGID" files are not defined, this is a finding.
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised information system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider threats and the advanced persistent threat.
CCE-93706-0 Encrypt Audit Records Sent With audispd Plugin Configure the operating system to encrypt the transfer of off-loaded audit records onto a different system or media from the system being audited. Uncomment the enable_krb5 option in
/etc/audit/audisp-remote.conf
, and set it with the following line:
enable_krb5 = yes
Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity.
CCE-93707-8 Configure audispd Plugin To Send Logs To Remote Server Configure the audispd plugin to off-load audit records onto a different system or media from the system being audited. Set the remote_server option in
/etc/audit/audisp-remote.conf
with an IP address or hostname of the system that the audispd plugin should send audit records to. For example
remote_server = logcollector
Information stored in one location is vulnerable to accidental or incidental deletion or alteration.Off-loading is a common process in information systems with limited audit storage capacity.
CCE-93708-6 Configure auditd space_left on Low Disk Space The auditd service can be configured to take an action when disk space is running low but prior to running out of space completely. Edit the file /etc/audit/auditd.conf. Add or modify the following line, substituting PERCENTAGE appropriately:
space_left = PERCENTAGE%
Set this value to at least 25 to cause the system to notify the user of an issue.
Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.
CCE-93709-4 Configure Time Service Maxpoll Interval The maxpoll should be configured to 10 in /etc/ntp.conf or /etc/chrony.conf (or /etc/chrony.d/) to continuously poll time servers. To configure maxpoll in /etc/ntp.conf or /etc/chrony.conf (or /etc/chrony.d/) add the following after each server, pool or peer entry:
maxpoll 10
to server directives. If using chrony, any pool directives should be configured too.
Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate. Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network. Organizations should consider endpoints that may not have regular access to the authoritative time server (e.g., mobile, teleworking, and tactical endpoints).
CCE-93710-2 Build and Test AIDE Database Run the following command to generate a new database:
$ sudo /usr/bin/aide --init
By default, the database will be written to the file /var/lib/aide/aide.db.new. Storing the database, the configuration file /etc/aide.conf, and the binary /usr/bin/aide (or hashes of these files), in a secure location (such as on read-only media) provides additional assurance about their integrity. The newly-generated database can be installed as follows:
$ sudo cp /var/lib/aide/aide.db.new /var/lib/aide/aide.db
To initiate a manual check, run the following command:
$ sudo /usr/bin/aide --check
If this check produces any unexpected output, investigate.
For AIDE to be effective, an initial database of "known-good" information about files must be captured and it should be able to be verified against the installed files.
CCE-93711-0 Configure Periodic Execution of AIDE At a minimum, AIDE should be configured to run a weekly scan. To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab:
05 4 * * * root /usr/bin/aide --check
To implement a weekly execution of AIDE at 4:05am using cron, add the following line to /etc/crontab:
05 4 * * 0 root /usr/bin/aide --check
AIDE can be executed periodically through other means; this is merely one example. The usage of cron's special time codes, such as @daily and @weekly is acceptable.
By default, AIDE does not install itself for periodic execution. Periodically running AIDE is necessary to reveal unexpected changes in installed files.

Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the operating system. Changes to operating system configurations can have unintended side effects, some of which may be relevant to security.

Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the operating system. The operating system's Information Management Officer (IMO)/Information System Security Officer (ISSO) and System Administrators (SAs) must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item.
CCE-93712-8 Ensure gpgcheck Enabled In Main zypper Configuration The gpgcheck option controls whether RPM packages' signatures are always checked prior to installation. To configure zypper to check package signatures before installing them, ensure the following line appears in /etc/zypp/zypp.conf in the [main] section:
gpgcheck=1
Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor.
Accordingly, patches, service packs, device drivers, or operating system components must be signed with a certificate recognized and approved by the organization.
Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This ensures the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. Certificates used to verify the software must be from an approved Certificate Authority (CA).
CCE-93713-6 Ensure Users Re-Authenticate for Privilege Escalation - sudo The sudo NOPASSWD and !authenticate option, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making sure that NOPASSWD and/or !authenticate do not exist in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/." Without re-authentication, users may access resources or perform tasks for which they do not have authorization.

When operating systems provide the capability to escalate a functional capability, it is critical that the user re-authenticate.
CCE-93714-4 Ensure Users Re-Authenticate for Privilege Escalation - sudo NOPASSWD The sudo NOPASSWD tag, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making sure that the NOPASSWD tag does not exist in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/. Without re-authentication, users may access resources or perform tasks for which they do not have authorization.

When operating systems provide the capability to escalate a functional capability, it is critical that the user re-authenticate.
CCE-93715-1 Ensure Users Re-Authenticate for Privilege Escalation - sudo !authenticate The sudo !authenticate option, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making sure that the !authenticate option does not exist in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/. Without re-authentication, users may access resources or perform tasks for which they do not have authorization.

When operating systems provide the capability to escalate a functional capability, it is critical that the user re-authenticate.
CCE-93716-9 Require Re-Authentication When Using the sudo Command The sudo timestamp_timeout tag sets the amount of time sudo password prompt waits. The default timestamp_timeout value is 5 minutes. The timestamp_timeout should be configured by making sure that the timestamp_timeout tag exists in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/. If the value is set to an integer less than 0, the user's time stamp will not expire and the user will not have to re-authenticate for privileged actions until the user's session is terminated. Without re-authentication, users may access resources or perform tasks for which they do not have authorization.

When operating systems provide the capability to escalate a functional capability, it is critical that the user re-authenticate.
CCE-93717-7 Configure Smart Card Certificate Status Checking Configure the operating system to do certificate status checking for PKI authentication. Modify all of the cert_policy lines in /etc/pam_pkcs11/pam_pkcs11.conf to include ocsp_on like so:
cert_policy = ca, ocsp_on, signature;
Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device.

Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards or similar secure authentication devices issued by an organization or identity provider.
CCE-93718-5 Configure SSSD's Memory Cache to Expire SSSD's memory cache should be configured to set to expire records after 300 seconds. To configure SSSD to expire memory cache, set memcache_timeout to 300 under the [nss] section in /etc/sssd/sssd.conf. For example:
[nss]
memcache_timeout = 300
If cached authentication information is out-of-date, the validity of the authentication information may be questionable.
CCE-93719-3 Configure SSSD to Expire Offline Credentials SSSD should be configured to expire offline credentials after 1 day. To configure SSSD to expire offline credentials, set offline_credentials_expiration to 1 under the [pam] section in /etc/sssd/sssd.conf. For example:
[pam]
offline_credentials_expiration = 1
If cached authentication information is out-of-date, the validity of the authentication information may be questionable.
CCE-93720-1 Ensure zypper Removes Previous Package Versions zypper should be configured to remove previous software components after new versions have been installed. To configure zypper to remove the previous software components after updating, set the solver.upgradeRemoveDroppedPackages to 1 in /etc/zypp/zypp.conf. Previous versions of software components that are not removed from the information system after updates have been installed may be exploited by some adversaries.
CCE-93721-9 Configure Systemd Timer Execution of AIDE At a minimum, AIDE should be configured to run a weekly scan. To implement a systemd service and a timer unit to run the service periodically: For example, if a systemd timer is expected to be started every day at 5AM
OnCalendar=*-*-* 05:00:0
[Timer]
section in the timer unit and a Unit section starting the AIDE check service unit should be referred.
AIDE provides a means to check if unauthorized changes are made to the system. AIDE itself does not setup a periodic execution, so in order to detect unauthorized changes a systemd service to run the check and a systemd timer to take care of periodical execution of that systemd service should be defined.
CCE-93722-7 Configure Notification of Post-AIDE Scan Details AIDE should notify appropriate personnel of the details of a scan after the scan has been run. If AIDE has already been configured for periodic execution in /etc/crontab, append the following line to the existing AIDE line:
 | /bin/mail -s "$(hostname) - AIDE Integrity Check" root@localhost
Otherwise, add the following line to /etc/crontab:
05 4 * * * root /usr/bin/aide --check | /bin/mail -s "$(hostname) - AIDE Integrity Check" root@localhost
AIDE can be executed periodically through other means; this is merely one example.
Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the operating system. Changes to operating system configurations can have unintended side effects, some of which may be relevant to security.

Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the operating system. The operating system's Information Management Officer (IMO)/Information System Security Officer (ISSO) and System Administrators (SAs) must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item.
CCE-93723-5 Record Attempts to Alter Process and Session Initiation Information utmp The audit system already collects process information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /var/run/utmp -p wa -k session
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /var/run/utmp -p wa -k session
Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
CCE-93724-3 Record Attempts to Alter Process and Session Initiation Information wtmp The audit system already collects process information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /var/log/wtmp -p wa -k session
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /var/log/wtmp -p wa -k session
Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
CCE-93725-0 Record Attempts to Alter Process and Session Initiation Information btmp The audit system already collects process information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /var/log/btmp -p wa -k session
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /var/log/btmp -p wa -k session
Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
CCE-93727-6 Configure audispd's Plugin network_failure_action On Network Failure Configure the action the operating system takes if there is an error sending audit records to a remote system. Edit the file /etc/audit/audisp-remote.conf. Add or modify the following line, substituting ACTION appropriately:
network_failure_action = ACTION
Set this value to single to cause the system to switch to single user mode for corrective action. Acceptable values also include syslog and halt. For certain systems, the need for availability outweighs the need to log all actions, and a different setting should be determined. This profile configures the action to be single.
Taking appropriate action when there is an error sending audit records to a remote system will minimize the possibility of losing audit records.
CCE-93728-4 Configure audispd's Plugin disk_full_action When Disk Is Full Configure the action the operating system takes if the disk the audit records are written to becomes full. Edit the file /etc/audit/audisp-remote.conf. Add or modify the following line, substituting ACTION appropriately:
disk_full_action = ACTION
Set this value to single to cause the system to switch to single user mode for corrective action. Acceptable values also include syslog and halt. For certain systems, the need for availability outweighs the need to log all actions, and a different setting should be determined.
Taking appropriate action in case of a filled audit storage volume will minimize the possibility of losing audit records.
CCE-93729-2 Set Password Retry Limit The pam_cracklib module's retry parameter controls the maximum number of times to prompt the user for the password before returning with error. Make sure it is configured with a value that is no more than 3. For example, retry=1. To reduce opportunities for successful guesses and brute-force attacks.
CCE-93730-0 Ensure PAM Displays Last Logon/Access Notification To configure the system to notify users of last logon/access using pam_lastlog, add or correct the pam_lastlog settings in /etc/pam.d/login to include showfailed option, such as:
session     required    pam_lastlog.so showfailed
And make sure that the silent option is not set for this specific line.
Users need to be aware of activity that occurs regarding their account. Providing users with information regarding the number of unsuccessful attempts that were made to login to their account allows the user to determine if any unauthorized activity has occurred and gives them an opportunity to notify administrators.
CCE-93731-8 Only Authorized Local User Accounts Exist on Operating System Enterprise Application tends to use the server or virtual machine exclusively. Besides the default operating system user, there should be only authorized local users required by the installed software groups and applications that exist on the operating system. The authorized user list can be customized in the refine value variable var_accounts_authorized_local_users_regex. OVAL regular expression is used for the user list. Configure the system so all accounts on the system are assigned to an active system, application, or user account. Remove accounts that do not support approved system activities or that allow for a normal user to perform administrative-level actions. To remove unauthorized system accounts, use the following command:
$ sudo userdel unauthorized_user
Accounts providing no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system.
CCE-93732-6 Ensure that System Accounts Do Not Run a Shell Upon Login Some accounts are not associated with a human user of the system, and exist to perform some administrative functions. Should an attacker be able to log into these accounts, they should not be granted access to a shell.

The login shell for each local account is stored in the last field of each line in /etc/passwd. System accounts are those user accounts with a user ID less than 1000. The user ID is stored in the third field. If any system account other than root has a login shell, disable it with the command:
$ sudo usermod -s /sbin/nologin account
Ensuring shells are not given to system accounts upon login makes it more difficult for attackers to make use of system accounts.
CCE-93733-4 Ensure sudo only includes the default configuration directory Administrators can configure authorized sudo users via drop-in files, and it is possible to include other directories and configuration files from the file currently being parsed. Make sure that /etc/sudoers only includes drop-in configuration files from /etc/sudoers.d, or that no drop-in file is included. Either the /etc/sudoers should contain only one #includedir directive pointing to /etc/sudoers.d, and no file in /etc/sudoers.d/ should include other files or directories; Or the /etc/sudoers should not contain any #include, @include, #includedir or @includedir directives. Note that the '#' character doesn't denote a comment in the configuration file. Some sudo configuration options allow users to run programs without re-authenticating. Use of these configuration options makes it easier for one compromised account to be used to compromise other accounts.
CCE-93734-2 Verify Only Root Has UID 0 If any account other than root has a UID of 0, this misconfiguration should be investigated and the accounts other than root should be removed or have their UID changed.
If the account is associated with system commands or applications the UID should be changed to one greater than "0" but less than "1000." Otherwise assign a UID greater than "1000" that has not already been assigned.
An account has root authority if it has a UID of 0. Multiple accounts with a UID of 0 afford more opportunity for potential intruders to guess a password for a privileged account. Proper configuration of sudo is recommended to afford multiple system administrators access to root privileges in an accountable manner.
CCE-93735-9 Ensure invoking users password for privilege escalation when using sudo The sudoers security policy requires that users authenticate themselves before they can use sudo. When sudoers requires authentication, it validates the invoking user's credentials. The expected output for:
 sudo cvtsudoers -f sudoers /etc/sudoers | grep -E '^Defaults !?(rootpw|targetpw|runaspw)$' 
 Defaults !targetpw
      Defaults !rootpw
      Defaults !runaspw 
or if cvtsudoers not supported:
 sudo find /etc/sudoers /etc/sudoers.d \( \! -name '*~' -a \! -name '*.*' \) -exec grep -E --with-filename '^[[:blank:]]*Defaults[[:blank:]](.*[[:blank:]])?!?\b(rootpw|targetpw|runaspw)' -- {} \; 
 /etc/sudoers:Defaults !targetpw
      /etc/sudoers:Defaults !rootpw
      /etc/sudoers:Defaults !runaspw 
If the rootpw, targetpw, or runaspw flags are defined and not disabled, by default the operating system will prompt the invoking user for the "root" user password.
CCE-93736-7 Ensure Home Directories are Created for New Users All local interactive user accounts, upon creation, should be assigned a home directory.

Configure the operating system to assign home directories to all new local interactive users by setting the CREATE_HOME parameter in /etc/login.defs to yes as follows:

CREATE_HOME yes
If local interactive users are not assigned a valid home directory, there is no place for the storage and control of files they should own.
CCE-93737-5 Ensure There Are No Accounts With Blank or Null Passwords Check the "/etc/shadow" file for blank passwords with the following command:
$ sudo awk -F: '!$2 {print $1}' /etc/shadow
If the command returns any results, this is a finding. Configure all accounts on the system to have a password or lock the account with the following commands: Perform a password reset:
$ sudo passwd [username]
Lock an account:
$ sudo passwd -l [username]
If an account has an empty password, anyone could log in and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.
CCE-93738-3 Prevent Login to Accounts With Empty Password If an account is configured for password authentication but does not have an assigned password, it may be possible to log into the account without authentication. Remove any instances of the nullok in password authentication configurations in /etc/pam.d/ to prevent logins with empty passwords. If an account has an empty password, anyone could log in and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.
CCE-93739-1 Remove Default Configuration to Disable Syscall Auditing By default, SUSE Linux Enterprise Micro 5 ships an audit rule to disable syscall auditing for performance reasons. To make sure that syscall auditing works, this line must be removed from /etc/audit/rules.d/audit.rules and /etc/audit/audit.rules:
-a task,never
Audit rules for syscalls do not take effect unless this line is removed.
CCE-93740-9 Remove User Host-Based Authentication Files The ~/.shosts (in each user's home directory) files list remote hosts and users that are trusted by the local system. To remove these files, run the following command to delete them from any location:
$ sudo find / -name '.shosts' -type f -delete
The .shosts files are used to configure host-based authentication for individual users or the system via SSH. Host-based authentication is not sufficient for preventing unauthorized access to the system, as it does not require interactive identification and authentication of a connection request, or for the use of two-factor authentication.
CCE-93741-7 Remove Host-Based Authentication Files The shosts.equiv file lists remote hosts and users that are trusted by the local system. To remove these files, run the following command to delete them from any location:
$ sudo rm /[path]/[to]/[file]/shosts.equiv
The shosts.equiv files are used to configure host-based authentication for the system via SSH. Host-based authentication is not sufficient for preventing unauthorized access to the system, as it does not require interactive identification and authentication of a connection request, or for the use of two-factor authentication.
CCE-93742-5 Configure AIDE to Verify Access Control Lists (ACLs) By default, the acl option is added to the FIPSR ruleset in AIDE. If using a custom ruleset or the acl option is missing, add acl to the appropriate ruleset. For example, add acl to the following line in /etc/aide.conf:
FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha256
AIDE rules can be configured in multiple ways; this is merely one example that is already configured by default. The remediation provided with this rule adds acl to all rule sets available in /etc/aide.conf
ACLs can provide permissions beyond those permitted through the file mode and must be verified by the file integrity tools.
CCE-93743-3 Configure AIDE to Verify Extended Attributes By default, the xattrs option is added to the FIPSR ruleset in AIDE. If using a custom ruleset or the xattrs option is missing, add xattrs to the appropriate ruleset. For example, add xattrs to the following line in /etc/aide.conf:
FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha256
AIDE rules can be configured in multiple ways; this is merely one example that is already configured by default. The remediation provided with this rule adds xattrs to all rule sets available in /etc/aide.conf
Extended attributes in file systems are used to contain arbitrary data and file metadata with security implications.
CCE-93744-1 Disable Ctrl-Alt-Del Reboot Activation By default, SystemD will reboot the system if the Ctrl-Alt-Del key sequence is pressed.

To configure the system to ignore the Ctrl-Alt-Del key sequence from the command line instead of rebooting the system, do either of the following:
ln -sf /dev/null /etc/systemd/system/ctrl-alt-del.target
or
systemctl mask ctrl-alt-del.target


Do not simply delete the /usr/lib/systemd/system/ctrl-alt-del.service file, as this file may be restored during future system updates.
A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.
CCE-93745-8 All Interactive Users Must Have A Home Directory Defined Assign home directories to all interactive users that currently do not have a home directory assigned. This rule checks if the home directory is properly defined in a folder which has at least one parent folder, like "user" in "/home/user" or "/remote/users/user". Therefore, this rule will report a finding for home directories like /users, /tmp or /. If local interactive users are not assigned a valid home directory, there is no place for the storage and control of files they should own.
CCE-93746-6 All Interactive Users Home Directories Must Exist Create home directories to all local interactive users that currently do not have a home directory assigned. Use the following commands to create the user home directory assigned in /etc/passwd:
$ sudo mkdir /home/USER
If a local interactive user has a home directory defined that does not exist, the user may be given access to the / directory as the current working directory upon logon. This could create a Denial of Service because the user would not be able to access their logon configuration files, and it may give them visibility to system files they normally would not be able to access.
CCE-93747-4 All Interactive User Home Directories Must Have mode 0750 Or Less Permissive Change the mode of interactive users home directories to 0750. To change the mode of interactive users home directory, use the following command:
$ sudo chmod 0750 /home/USER
Excessive permissions on local interactive user home directories may allow unauthorized access to user files by other users.
CCE-93748-2 All Interactive User Home Directories Must Be Group-Owned By The Primary Group Change the group owner of interactive users home directory to the group found in /etc/passwd. To change the group owner of interactive users home directory, use the following command:
$ sudo chgrp USER_GROUP /home/USER
This rule ensures every home directory related to an interactive user is group-owned by an interactive user. It also ensures that interactive users are group-owners of one and only one home directory.
If the Group Identifier (GID) of a local interactive users home directory is not the same as the primary GID of the user, this would allow unauthorized access to the users files, and users that share the same group may not be able to access files that they legitimately should.
CCE-93749-0 Ensure All User Initialization Files Have Mode 0740 Or Less Permissive Set the mode of the user initialization files to 0740 with the following command:
$ sudo chmod 0740 /home/USER/.INIT_FILE
Local initialization files are used to configure the user's shell environment upon logon. Malicious modification of these files could compromise accounts upon logon.
CCE-93750-8 The PAM configuration should not be changed automatically Verify the SUSE operating system is configured to not overwrite Pluggable Authentication Modules (PAM) configuration on package changes. pam-config is a command line utility that automatically generates a system PAM configuration as packages are installed, updated or removed from the system. pam-config removes configurations for PAM modules and parameters that it does not know about. It may render ineffective PAM configuration by the system administrator and thus impact system security.
CCE-93751-6 Verify Permissions on SSH Server Private *_key Key Files SSH server private keys - files that match the /etc/ssh/*_key glob, have to have restricted permissions. If those files are owned by the root user and the root group, they have to have the 0640 permission or stricter. If an unauthorized user obtains the private SSH host key file, the host could be impersonated.
CCE-93752-4 Ensure System is Not Acting as a Network Sniffer The system should not be acting as a network sniffer, which can capture all traffic on the network to which it is connected. Run the following to determine if any interface is running in promiscuous mode:
$ ip link | grep PROMISC
Promiscuous mode of an interface can be disabled with the following command:
$ sudo ip link set dev device_name multicast off promisc off
Network interfaces in promiscuous mode allow for the capture of all network traffic visible to the system. If unauthorized individuals can access these applications, it may allow them to collect information such as logon IDs, passwords, and key exchanges between systems.

If the system is being used to perform a network troubleshooting function, the use of these tools must be documented with the Information Systems Security Manager (ISSM) and restricted to only authorized personnel.
CCE-93753-2 Ensure the Default Umask is Set Correctly in login.defs To ensure the default umask controlled by /etc/login.defs is set properly, add or correct the UMASK setting in /etc/login.defs to read as follows:
UMASK 027
The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read and written to by unauthorized users.
CCE-93754-0 Disable GDM Unattended or Automatic Login The GNOME Display Manager (GDM) can allow users to automatically login without user interaction or credentials or unattended login. User should always be required to authenticate themselves to the system that they are authorized to use. To disable user ability to automatically login to the system, set the DISPLAYMANAGER_AUTOLOGIN="" or DISPLAYMANAGER_PASSWORD_LESS_LOGIN="no" in the /etc/sysconfig/displaymanager. For example:
DISPLAYMANAGER_AUTOLOGIN=""
DISPLAYMANAGER_PASSWORD_LESS_LOGIN="no"
Failure to restrict system access to authenticated users negatively impacts operating system security.
CCE-93755-7 Check that vlock is installed to allow session locking The SUSE Linux Enterprise Micro 5 operating system must have vlock installed to allow for session locking. The kbd package can be installed with the following command:
$ sudo zypper install kbd
A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Regardless of where the session lock is determined and implemented, once invoked, the session lock must remain in place until the user reauthenticates. No other activity aside from reauthentication must unlock the system.
CCE-93756-5 Ensure the audit Subsystem is Installed The audit package should be installed. The auditd service is an access monitoring and accounting daemon, watching system calls to audit any access, in comparison with potential local access control policy such as SELinux policy.
CCE-93758-1 Install AIDE The aide package can be installed with the following command:
$ sudo zypper install aide
The AIDE package must be installed if it is to be available for integrity checking.
CCE-93760-7 Encrypt Partitions SUSE Linux Enterprise Micro 5 natively supports partition encryption through the Linux Unified Key Setup-on-disk-format (LUKS) technology. The easiest way to encrypt a partition is during installation time.

For manual installations, select the Encrypt checkbox during partition creation to encrypt the partition. When this option is selected the system will prompt for a passphrase to use in decrypting the partition. The passphrase will subsequently need to be entered manually every time the system boots.

Detailed information on encrypting partitions using LUKS or LUKS ciphers can be found on the SUSE Linux Enterprise Micro 5 Documentation web site:
https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-security-cryptofs.html .
The risk of a system's physical compromise, particularly mobile systems such as laptops, places its data at risk of compromise. Encrypting this data mitigates the risk of its loss if the system is lost.
CCE-93761-5 Install Smart Card Packages For Multifactor Authentication Configure the operating system to implement multifactor authentication by installing the required package with the following command: The pam_pkcs11 package can be installed with the following command:
$ sudo zypper install pam_pkcs11
The mozilla-nss package can be installed with the following command:
$ sudo zypper install mozilla-nss
The mozilla-nss-tools package can be installed with the following command:
$ sudo zypper install mozilla-nss-tools
The pcsc-ccid package can be installed with the following command:
$ sudo zypper install pcsc-ccid
The pcsc-lite package can be installed with the following command:
$ sudo zypper install pcsc-lite
The pcsc-tools package can be installed with the following command:
$ sudo zypper install pcsc-tools
The opensc package can be installed with the following command:
$ sudo zypper install opensc
The coolkey package can be installed with the following command:
$ sudo zypper install coolkey
Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device.

Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards or similar secure authentication devices issued by an organization or identity provider.
CCE-93762-3 Set Password Strength Minimum Uppercase Characters The pam_cracklib module's ucredit= parameter controls requirements for usage of uppercase letters in a password. When set to a negative number, any password will be required to contain that many uppercase characters. When set to a positive number, pam_cracklib will grant +1 additional length credit for each uppercase character. Add ucredit=-1 after pam_cracklib.so to require use of an upper case character in passwords. Requiring a minimum number of uppercase characters makes password guessing attacks more difficult by ensuring a larger search space.
CCE-93763-1 Set Password Strength Minimum Lowercase Characters The pam_cracklib module's lcredit= parameter controls requirements for usage of lowercase letters in a password. When set to a negative number, any password will be required to contain that many lowercase characters. When set to a positive number, pam_cracklib will grant +1 additional length credit for each lowercase character. Add lcredit=-1 after pam_cracklib.so to require use of a lowercase character in passwords. Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.
CCE-93764-9 Set Password Strength Minimum Digit Characters The pam_cracklib module's dcredit parameter controls requirements for usage of digits in a password. When set to a negative number, any password will be required to contain that many digits. When set to a positive number, pam_cracklib will grant +1 additional length credit for each digit. Add dcredit=-1 after pam_cracklib.so to require use of a digit in passwords. Requiring digits makes password guessing attacks more difficult by ensuring a larger search space.
CCE-93765-6 Set Password Strength Minimum Different Characters The pam_cracklib module's difok parameter controls requirements for usage of different characters during a password change. The number of changed characters refers to the number of changes required with respect to the total number of positions in the current password. In other words, characters may be the same within the two passwords; however, the positions of the like characters must be different. Make sure the difok parameter for the pam_cracklib module is configured to greater than or equal to 8. Requiring a minimum number of different characters during password changes ensures that newly changed passwords should not resemble previously compromised ones. Note that passwords which are changed on compromised systems will still be compromised, however.
CCE-93766-4 Set Password Minimum Length The pam_cracklib module's minlen parameter controls requirements for minimum characters required in a password. Add minlen=15 to set minimum password length requirements. Password length is one factor of several that helps to determine strength and how long it takes to crack a password. Use of more characters in a password helps to exponentially increase the time and/or resources required to compromise the password.
CCE-93767-2 Set Password Strength Minimum Special Characters The pam_cracklib module's ocredit= parameter controls requirements for usage of special (or ``other'') characters in a password. When set to a negative number, any password will be required to contain that many special characters. When set to a positive number, pam_cracklib will grant +1 additional length credit for each special character. Make sure the ocredit parameter for the pam_cracklib module is set to less than or equal to -1. For example, ocredit=-1. Requiring a minimum number of special characters makes password guessing attacks more difficult by ensuring a larger search space.
CCE-93768-0 Enable auditd Service The auditd service is an essential userspace component of the Linux Auditing System, as it is responsible for writing audit records to disk. The auditd service can be enabled with the following command:
$ sudo systemctl enable auditd.service
Without establishing what type of events occurred, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Ensuring the auditd service is active ensures audit records generated by the kernel are appropriately recorded.

Additionally, a properly configured audit subsystem ensures that actions of individual system users can be uniquely traced to those users so they can be held accountable for their actions.
CCE-93769-8 Verify firewalld Enabled The firewalld service can be enabled with the following command:
$ sudo systemctl enable firewalld.service
Access control methods provide the ability to enhance system security posture by restricting services and known good IP addresses and address ranges. This prevents connections from unknown hosts and protocols.
CCE-93770-6 Install the OpenSSH Server Package The openssh-server package should be installed. The openssh-server package can be installed with the following command:
$ sudo zypper install openssh-server
Without protection of the transmitted information, confidentiality, and integrity may be compromised because unprotected communications can be intercepted and either read or altered.
CCE-93771-4 Enable the OpenSSH Service The SSH server service, sshd, is commonly needed. The sshd service can be enabled with the following command:
$ sudo systemctl enable sshd.service
Without protection of the transmitted information, confidentiality, and integrity may be compromised because unprotected communications can be intercepted and either read or altered.

This checklist item applies to both internal and external networks and all types of information system components from which information can be transmitted (e.g., servers, mobile devices, notebook computers, printers, copiers, scanners, etc). Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification.
CCE-93772-2 Disable the Automounter The autofs daemon mounts and unmounts filesystems, such as user home directories shared via NFS, on demand. In addition, autofs can be used to handle removable media, and the default configuration provides the cdrom device as /misc/cd. However, this method of providing access to removable media is not common, so autofs can almost always be disabled if NFS is not in use. Even if NFS is required, it may be possible to configure filesystem mounts statically by editing /etc/fstab rather than relying on the automounter.

The autofs service can be disabled with the following command:
$ sudo systemctl mask --now autofs.service
Disabling the automounter permits the administrator to statically control filesystem mounting through /etc/fstab.

Additionally, automatically mounting filesystems permits easy introduction of unknown devices, thereby facilitating malicious activity.
CCE-93773-0 Disable KDump Kernel Crash Analyzer (kdump) The kdump service provides a kernel crash dump analyzer. It uses the kexec system call to boot a secondary kernel ("capture" kernel) following a system crash, which can load information from the crashed kernel for analysis. The kdump service can be disabled with the following command:
$ sudo systemctl mask --now kdump.service
Kernel core dumps may contain the full contents of system memory at the time of the crash. Kernel core dumps consume a considerable amount of disk space and may result in denial of service by exhausting the available space on the target file system partition. Unless the system is used for kernel development or testing, there is little need to run the kdump service.
CCE-93774-8 Verify All Account Password Hashes are Shadowed with SHA512 Verify the operating system requires the shadow password suite configuration be set to encrypt interactive user passwords using a strong cryptographic hash. Check that the interactive user account passwords are using a strong password hash with the following command:
$ sudo cut -d: -f2 /etc/shadow
$6$kcOnRq/5$NUEYPuyL.wghQwWssXRcLRFiiru7f5JPV6GaJhNC2aK5F3PZpE/BCCtwrxRc/AInKMNX3CdMw11m9STiql12f/
Password hashes ! or * indicate inactive accounts not available for logon and are not evaluated. If any interactive user password hash does not begin with $6, this is a finding.
Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised.
CCE-93775-5 Set Deny For Failed Password Attempts The SUSE Linux Enterprise Micro 5 operating system must lock an account after - at most - 3 consecutive invalid access attempts. By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. To configure the operating system to lock an account after three unsuccessful consecutive access attempts using pam_tally2.so, modify the content of both /etc/pam.d/common-auth and /etc/pam.d/common-account as follows:

  • add or modify the pam_tally2.so module line in /etc/pam.d/common-auth to ensure both onerr=fail and deny= are present. For example:
    auth required pam_tally2.so onerr=fail silent audit deny=
  • add or modify the following line in /etc/pam.d/common-account:
    account required pam_tally2.so
CCE-93776-3 Verify that Local Logs of the audit Daemon are not World-Readable Files containing sensitive information should be protected by restrictive permissions. Most of the time, there is no need that these files need to be read by any non-root user. Check that "permissions.local" file contains the correct permissions rules with the following command:
# grep -i audit /etc/permissions.local

/var/log/audit/ root:root 600
/var/log/audit/audit.log root:root 600
/etc/audit/audit.rules root:root 640
/etc/audit/rules.d/audit.rules root:root 640
Without the capability to restrict which roles and individuals can select which events are audited, unauthorized personnel may be able to prevent the auditing of critical events. Misconfigured audits may degrade the system's performance by overwhelming the audit log. Misconfigured audits may also make it more difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.
CCE-93778-9 Set Boot Loader Password in grub2 The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings.

Since plaintext passwords are a security risk, generate a hash for the password by running the following command:
# grub2-mkpasswd-pbkdf2
When prompted, enter the password that was selected.

Using the hash from the output, modify the /etc/grub.d/40_custom file with the following content:
set superusers="boot"
password_pbkdf2 boot grub.pbkdf2.sha512.VeryLongString
NOTE: the bootloader superuser account and password MUST differ from the root account and password. Once the superuser password has been added, update the grub.cfg file by running:
grub2-mkconfig -o /boot/grub2/grub.cfg
Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.
CCE-93779-7 Set the UEFI Boot Loader Password The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings.

Since plaintext passwords are a security risk, generate a hash for the password by running the following command:
# grub2-mkpasswd-pbkdf2
When prompted, enter the password that was selected.

Using the hash from the output, modify the /etc/grub.d/40_custom file with the following content:
set superusers="boot"
password_pbkdf2 boot grub.pbkdf2.sha512.VeryLongString
NOTE: the bootloader superuser account and password MUST differ from the root account and password. Once the superuser password has been added, update the grub.cfg file by running:
grub2-mkconfig -o /boot/grub2/grub.cfg
Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.
CCE-93780-5 Ensure All Accounts on the System Have Unique User IDs Change user IDs (UIDs), or delete accounts, so each has a unique name. To assure accountability and prevent unauthenticated access, interactive users must be identified and authenticated to prevent potential misuse and compromise of the system.
CCE-93781-3 Never Automatically Remove or Disable Emergency Administrator Accounts Emergency accounts are privileged accounts that are established in response to crisis situations where the need for rapid account activation is required. Therefore, emergency account activation may bypass normal account authorization processes. If these accounts are automatically disabled, system maintenance during emergencies may not be possible, thus adversely affecting system availability. Check to see if an emergency administrator account password or account expires with the following command:
# sudo chage -l [Emergency_Administrator]

Password expires:never
If Password expires or Account expires is set to anything other than never, this is a finding.
Emergency accounts are different from infrequently used accounts (i.e., local logon accounts used by the organization's system administrators when network or normal logon/access is not available). Infrequently used accounts are not subject to automatic termination dates. Emergency accounts are accounts created in response to crisis situations, usually for use by maintenance personnel. The automatic expiration or disabling time period may be extended as needed until the crisis is resolved; however, it must not be extended indefinitely. A permanent account should be established for privileged users who need long-term maintenance accounts. To address access requirements the SUSE operating system can be integrated with enterprise-level authentication/access mechanisms that meet or exceed access control policy requirements.
CCE-93782-1 Assign Expiration Date to Temporary Accounts Temporary accounts are established as part of normal account activation procedures when there is a need for short-term accounts. In the event temporary accounts are required, configure the system to terminate them after a documented time period. For every temporary account, run the following command to set an expiration date on it, substituting USER and YYYY-MM-DD appropriately:
$ sudo chage -E YYYY-MM-DD USER
YYYY-MM-DD indicates the documented expiration date for the account. For U.S. Government systems, the operating system must be configured to automatically terminate these types of accounts after a period of 72 hours.
If temporary user accounts remain active when no longer needed or for an excessive period, these accounts may be used to gain unauthorized access. To mitigate this risk, automated termination of all temporary accounts must be set upon account creation.
CCE-93784-7 Disable Modprobe Loading of USB Storage Driver To prevent USB storage devices from being used, configure the kernel module loading system to prevent automatic loading of the USB storage driver. To configure the system to prevent the usb-storage kernel module from being loaded, add the following line to the file /etc/modprobe.d/usb-storage.conf:
install usb-storage /bin/false
This entry will cause a non-zero return value during a usb-storage module installation and additionally convey the meaning of the entry to the user in form of an error message. If you would like to omit a non-zero return value and an error message, you may want to add a different line instead (both /bin/true and /bin/false are allowed by OVAL and will be accepted by the scan):
install usb-storage /bin/true
This will prevent the modprobe program from loading the usb-storage module, but will not prevent an administrator (or another program) from using the insmod program to load the module manually.
USB storage devices such as thumb drives can be used to introduce malicious software.
CCE-93785-4 Verify '/proc/sys/crypto/fips_enabled' exists On a system where FIPS 140-2 mode is enabled, /proc/sys/crypto/fips_enabled must exist. To verify FIPS mode, run the following command:
cat /proc/sys/crypto/fips_enabled
Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The operating system must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated.
CCE-93786-2 The operating system must restrict privilege elevation to authorized personnel The sudo command allows a user to execute programs with elevated (administrator) privileges. It prompts the user for their password and confirms your request to execute a command by checking a file, called sudoers. Restrict privileged actions by removing the following entries from the sudoers file: ALL ALL=(ALL) ALL ALL ALL=(ALL:ALL) ALL If the "sudoers" file is not configured correctly, any user defined on the system can initiate privileged actions on the target system.
CCE-93787-0 Ensure /var/log/audit Located On Separate Partition Audit logs are stored in the /var/log/audit directory. Ensure that /var/log/audit has its own partition or logical volume at installation time, or migrate it using LVM. Make absolutely certain that it is large enough to store all audit logs that will be created by the auditing daemon. Placing /var/log/audit in its own partition enables better separation between audit files and other files, and helps ensure that auditing cannot be halted due to the partition running out of space.
CCE-93788-8 Configure auditd space_left Action on Low Disk Space The auditd service can be configured to take an action when disk space starts to run low. Edit the file /etc/audit/auditd.conf. Modify the following line, substituting ACTION appropriately:
space_left_action = ACTION
Possible values for ACTION are described in the auditd.conf man page. These include:
  • syslog
  • email
  • exec
  • suspend
  • single
  • halt
Set this to email (instead of the default, which is suspend) as it is more likely to get prompt attention. Acceptable values also include suspend, single, and halt.
Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.
CCE-93789-6 Ensure that Users Path Contains Only Local Directories Ensure that all interactive user initialization files executable search path statements do not contain statements that will reference a working directory other than the users home directory. The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory (other than the users home directory), executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon or two consecutive colons, this is interpreted as the current working directory. If deviations from the default system search path for the local interactive user are required, they must be documented with the Information System Security Officer (ISSO).
CCE-93790-4 User Initialization Files Must Not Run World-Writable Programs Set the mode on files being executed by the user initialization files with the following command:
$ sudo chmod o-w FILE
If user start-up files execute world-writable programs, especially in unprotected directories, they could be maliciously modified to destroy user files or otherwise compromise the system at the user level. If the system is compromised at the user level, it is easier to elevate privileges to eventually compromise the system at the root and network level.
CCE-93791-2 Add nosuid Option to /home The nosuid mount option can be used to prevent execution of setuid programs in /home. The SUID and SGID permissions should not be required in these user data directories. Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of /home. The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from user home directory partitions.
CCE-93792-0 Add nosuid Option to Removable Media Partitions The nosuid mount option prevents set-user-identifier (SUID) and set-group-identifier (SGID) permissions from taking effect. These permissions allow users to execute binaries with the same permissions as the owner and group of the file respectively. Users should not be allowed to introduce SUID and SGID files into the system via partitions mounted from removable media. Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of any removable media partitions. The presence of SUID and SGID executables should be tightly controlled. Allowing users to introduce SUID or SGID binaries from partitions mounted off of removable media would allow them to introduce their own highly-privileged programs.
CCE-93793-8 Mount Remote Filesystems with nosuid Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of any NFS mounts. NFS mounts should not present suid binaries to users. Only vendor-supplied suid executables should be installed to their default location on the local filesystem.
CCE-93794-6 Mount Remote Filesystems with noexec Add the noexec option to the fourth column of /etc/fstab for the line which controls mounting of any NFS mounts. The noexec mount option causes the system not to execute binary files. This option must be used for mounting any file system not containing approved binary files as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.
CCE-93795-3 Ensure All World-Writable Directories Are Group Owned by a System Account All directories in local partitions which are world-writable should be group owned by root or another system account. If any world-writable directories are not group owned by a system account, this should be investigated. Following this, the files should be deleted or assigned to an appropriate group. Allowing a user account to group own a world-writable directory is undesirable because it allows the owner of that directory to remove or replace any files that may be placed in the directory by other users.
CCE-93796-1 Ensure /home Located On Separate Partition If user home directories will be stored locally, create a separate partition for /home at installation time (or migrate it later using LVM). If /home will be mounted from another system such as an NFS server, then creating a separate partition is not necessary at installation time, and the mountpoint can instead be configured later. Ensuring that /home is mounted on its own partition enables the setting of more restrictive mount options, and also helps ensure that users cannot trivially fill partitions used for log or audit data storage.
CCE-93797-9 Ensure /var Located On Separate Partition The /var directory is used by daemons and other system services to store frequently-changing data. Ensure that /var has its own partition or logical volume at installation time, or migrate it using LVM. Ensuring that /var is mounted on its own partition enables the setting of more restrictive mount options. This helps protect system services such as daemons or other programs which use it. It is not uncommon for the /var directory to contain world-writable directories installed by other software packages.
CCE-93798-7 Ensure All Files Are Owned by a User If any files are not owned by a user, then the cause of their lack of ownership should be investigated. Following this, the files should be deleted or assigned to an appropriate user. Locate the mount points related to local devices by the following command:
$ findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)
For all mount points listed by the previous command, it is necessary to search for files which do not belong to a valid user using the following command:
$ sudo find MOUNTPOINT -xdev -nouser 2>/dev/null
Unowned files do not directly imply a security problem, but they are generally a sign that something is amiss. They may be caused by an intruder, by incorrect software installation or draft software removal, or by failure to remove all files belonging to a deleted account, or other similar cases. The files should be repaired so they will not cause problems when accounts are created in the future, and the cause should be discovered and addressed.
CCE-93799-5 Ensure All Files Are Owned by a Group If any file is not group-owned by a valid defined group, the cause of the lack of group-ownership must be investigated. Following this, those files should be deleted or assigned to an appropriate group. The groups need to be defined in /etc/group or in /usr/lib/group if nss-altfiles are configured to be used in /etc/nsswitch.conf. Locate the mount points related to local devices by the following command:
$ findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)
For all mount points listed by the previous command, it is necessary to search for files which do not belong to a valid group using the following command:
$ sudo find MOUNTPOINT -xdev -nogroup 2>/dev/null
Unowned files do not directly imply a security problem, but they are generally a sign that something is amiss. They may be caused by an intruder, by incorrect software installation or draft software removal, or by failure to remove all files belonging to a deleted account, or other similar cases. The files should be repaired so they will not cause problems when accounts are created in the future, and the cause should be discovered and addressed.
CCE-93800-1 Enable Smart Card Logins in PAM This requirement only applies to components where this is specific to the function of the device or has the concept of an organizational user (e.g., VPN, proxy capability). This does not apply to authentication for the purpose of configuring the device itself (management). Check that the pam_pkcs11.so option is configured in the etc/pam.d/common-auth file with the following command:
# grep pam_pkcs11.so /etc/pam.d/common-auth

auth sufficient pam_pkcs11.so
For general information about enabling smart card authentication, consult the documentation at:
Smart card login provides two-factor authentication stronger than that provided by a username and password combination. Smart cards leverage PKI (public key infrastructure) in order to provide and verify credentials. Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device. Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards or similar secure authentication devices issued by an organization or identity provider.
CCE-93801-9 Verify that System Executable Directories Have Restrictive Permissions System executables are stored in the following directories by default:
/bin
/sbin
/usr/bin
/usr/sbin
/usr/local/bin
/usr/local/sbin
These directories should not be group-writable or world-writable. If any directory DIR in these directories is found to be group-writable or world-writable, correct its permission with the following command:
$ sudo chmod go-w DIR
System binaries are executed by privileged users, as well as system services, and restrictive permissions are necessary to ensure execution of these programs cannot be co-opted.
CCE-93802-7 Modify the System Login Banner To configure the system login banner edit /etc/issue. Replace the default text with a message compliant with the local site policy or a legal disclaimer. The DoD required text is either:

You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access controls) to protect USG interests -- not for your personal benefit or privacy.
-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.


OR:

I've read & consent to terms in IS user agreem't.
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.

System use notifications are required only for access via login interfaces with human users and are not required when such human interfaces do not exist.
CCE-93803-5 A remote time server for Chrony is configured Chrony is a daemon which implements the Network Time Protocol (NTP). It is designed to synchronize system clocks across a variety of systems and use a source that is highly accurate. More information on chrony can be found at https://chrony-project.org/. Chrony can be configured to be a client and/or a server. Add or edit server or pool lines to /etc/chrony.conf as appropriate:
server <remote-server>
Alternatively, server or pool directives can be specified in files included via sourcedir or confdir directives in /etc/chrony.conf. When using sourcedir, create .sources files in the specified directory:
# In /etc/chrony.conf:
sourcedir /etc/chrony/sources.d

# In /etc/chrony/sources.d/ntp.sources:
server 0.pool.ntp.org
When using confdir, create .conf files in the specified directory:
# In /etc/chrony.conf:
confdir /etc/chrony/conf.d

# In /etc/chrony/conf.d/ntp-servers.conf:
pool 1.pool.ntp.org
Multiple servers may be configured.
If chrony is in use on the system proper configuration is vital to ensuring time synchronization is working properly.
CCE-93804-3 Ensure Software Patches Installed If the system is configured for online updates, invoking the following command will list available security updates:
$ sudo zypper refresh && sudo zypper list-patches -g security


NOTE: U.S. Defense systems are required to be patched within 30 days or sooner as local policy dictates.
Installing software updates is a fundamental mitigation against the exploitation of publicly-known vulnerabilities. If the most recent security patches and updates are not installed, unauthorized users may take advantage of weaknesses in the unpatched software. The lack of prompt attention to patching could result in a system compromise.
CCE-93805-0 Set Interactive Session Timeout Setting the TMOUT option in /etc/profile ensures that all user sessions will terminate based on inactivity. A value of 0 (zero) disables the automatic logout feature and is therefore not a compliant setting. The value of TMOUT should be a positive integer, exported, and read only. The TMOUT setting in /etc/profile.d/autologout.sh should read as follows:
TMOUT=600
readonly TMOUT export TMOUT
Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended.
CCE-93834-0 Configure auditd max_log_file_action Upon Reaching Maximum Log Size The default action to take when the logs reach their maximum size is to rotate the log files, discarding the oldest one. To configure the action taken by auditd, add or correct the line in /etc/audit/auditd.conf:
max_log_file_action = ACTION
Possible values for ACTION are described in the auditd.conf man page. These include:
  • ignore
  • syslog
  • suspend
  • rotate
  • keep_logs
Set the ACTION to rotate. The setting is case-insensitive.
Automatically rotating logs (by setting this to rotate) minimizes the chances of the system unexpectedly running out of disk space by being overwhelmed with log data. However, for systems that must never discard log data, or which use external processes to transfer it and reclaim space, keep_logs can be employed.
CCE-93835-7 Configure auditd Max Log File Size Determine the amount of audit data (in megabytes) which should be retained in each log file. Edit the file /etc/audit/auditd.conf. Add or modify the following line, substituting the correct value of 6 for STOREMB:
max_log_file = STOREMB
Set the value to 6 (MB) or higher for general-purpose systems. Larger values, of course, support retention of even more audit data.
The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.
CCE-93836-5 Configure auditd admin_space_left Action on Low Disk Space The auditd service can be configured to take an action when disk space is running low but prior to running out of space completely. Edit the file /etc/audit/auditd.conf. Add or modify the following line, substituting ACTION appropriately:
admin_space_left_action = ACTION
Set this value to single to cause the system to switch to single user mode for corrective action. Acceptable values also include suspend and halt. For certain systems, the need for availability outweighs the need to log all actions, and a different setting should be determined. Details regarding all possible values for ACTION are described in the auditd.conf man page.
Administrators should be made aware of an inability to record audit records. If a separate partition or logical volume of adequate size is used, running low on space for audit records should never occur.
CCE-93837-3 Record Attempts to Alter the localtime File If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/localtime -p wa -k audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /etc/localtime -p wa -k audit_time_rules
Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.
CCE-93838-1 Record Attempts to Alter Time Through stime If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined system calls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules
Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.
CCE-93839-9 Record attempts to alter time through settimeofday If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules
Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.
CCE-93840-7 Record attempts to alter time through adjtimex If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules
Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.
CCE-93841-5 Record Attempts to Alter Logon and Logout Events - faillog The audit system already collects login information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /var/log/faillog -p wa -k logins
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /var/log/faillog -p wa -k logins
Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
CCE-93842-3 Ensure auditd Collects Information on Kernel Module Loading - init_module To capture kernel module loading and unloading events, use the following line, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S init_module -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the line to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the line to file /etc/audit/audit.rules.
The addition of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.
CCE-93843-1 Ensure auditd Collects Information on Kernel Module Loading and Unloading To capture kernel module loading and unloading events, use following lines, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S init_module,finit_module,delete_module -F key=modules
The place to add the lines depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the lines to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the lines to file /etc/audit/audit.rules.
The addition/removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.
CCE-93844-9 Record Unsuccessful Access Attempts to Files - truncate At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
CCE-93845-6 Record Unsuccessful Access Attempts to Files - openat At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
CCE-93846-4 Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful) At a minimum the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
CCE-93847-2 Record Unsuccessful Access Attempts to Files - ftruncate At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
CCE-93848-0 Record Unsuccessful Access Attempts to Files - creat At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
CCE-93849-8 Ensure auditd Collects File Deletion Events by User - unlink At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete
Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.
CCE-93850-6 Ensure auditd Collects File Deletion Events by User - unlinkat At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.
CCE-93851-4 Ensure auditd Collects File Deletion Events by User - renameat At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete
Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.
CCE-93852-2 Ensure auditd Collects File Deletion Events by User - rename At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete
Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.
CCE-93853-0 Record Events that Modify the System's Discretionary Access Controls - setxattr At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93854-8 Record Events that Modify the System's Discretionary Access Controls - removexattr At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93855-5 Record Events that Modify the System's Discretionary Access Controls - lsetxattr At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93856-3 Record Events that Modify the System's Discretionary Access Controls - lremovexattr At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93857-1 Record Events that Modify the System's Discretionary Access Controls - fsetxattr At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93858-9 Record Events that Modify the System's Discretionary Access Controls - fchownat At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93859-7 Record Events that Modify the System's Discretionary Access Controls - fchown At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93860-5 Record Events that Modify the System's Discretionary Access Controls - fchmodat At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93861-3 Record Events that Modify the System's Discretionary Access Controls - chown At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93862-1 Record Events that Modify the System's Discretionary Access Controls - chmod At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
CCE-93863-9 Record Attempts to perform maintenance activities The SUSE Linux Enterprise Micro 5 operating system must generate audit records for privileged activities, nonlocal maintenance, diagnostic sessions and other system-level access. Verify the operating system audits activities performed during nonlocal maintenance and diagnostic sessions. Run the following command:
$ sudo auditctl -l | grep sudo.log
-w /var/log/sudo.log -p wa -k maintenance
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /var/log/sudo.log -p wa -k maintenance
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /var/log/sudo.log -p wa -k maintenance
If events associated with nonlocal administrative access or diagnostic sessions are not logged, a major tool for assessing and investigating attacks would not be available. This requirement addresses auditing-related issues associated with maintenance tools used specifically for diagnostic and repair actions on organizational information systems. Nonlocal maintenance and diagnostic activities are those activities conducted by individuals communicating through a network, either an external network (e.g., the internet) or an internal network. Local maintenance and diagnostic activities are those activities carried out by individuals physically present at the information system or information system component and not communicating across a network connection. This requirement applies to hardware/software diagnostic test equipment or tools. This requirement does not cover hardware/software components that may support information system maintenance, yet are a part of the system, for example, the software implementing "ping," "ls," "ipconfig," or the hardware and software implementing the monitoring port of an Ethernet switch.
CCE-93864-7 Record Events that Modify User/Group Information - /etc/gshadow If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.
CCE-93865-4 Record Attempts to Alter Process and Session Initiation Information The audit system already collects process information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d in order to watch for attempted manual edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file in order to watch for attempted manual edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session
Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
CCE-93866-2 Record Events that Modify the System's Network Environment If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification

-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.
CCE-93867-0 Record Events that Modify the System's Mandatory Access Controls in usr/share If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /usr/share/selinux/ -p wa -k MAC-policy
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules:
-w /usr/share/selinux/ -p wa -k MAC-policy
The system's mandatory access policy (SELinux) should not be arbitrarily changed by anything other than administrator action. All changes to MAC policy should be audited.
CCE-93868-8 Record Events that Modify the System's Mandatory Access Controls If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/selinux/ -p wa -k MAC-policy
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-w /etc/selinux/ -p wa -k MAC-policy
The system's mandatory access policy (SELinux or Apparmor) should not be arbitrarily changed by anything other than administrator action. All changes to MAC policy should be audited.
CCE-93869-6 Make the auditd Configuration Immutable If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d in order to make the auditd configuration immutable:
-e 2
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file in order to make the auditd configuration immutable:
-e 2
With this setting, a reboot will be required to change any audit rules.
Making the audit configuration immutable prevents accidental as well as malicious modification of the audit rules, although it may be problematic if legitimate changes are needed during system operation.
CCE-93870-4 Extend Audit Backlog Limit for the Audit Daemon To improve the kernel capacity to queue all log events, even those which occurred prior to the audit daemon, add the argument audit_backlog_limit=8192 to the default GRUB 2 command line for the Linux operating system. Configure the default Grub2 kernel command line to contain audit_backlog_limit=8192 as follows:
# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) audit_backlog_limit=8192"
audit_backlog_limit sets the queue length for audit events awaiting transfer to the audit daemon. Until the audit daemon is up and running, all log messages are stored in this queue. If the queue is overrun during boot process, the action defined by audit failure flag is taken.
CCE-93871-2 Enable Auditing for Processes Which Start Prior to the Audit Daemon To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument audit=1 to the default GRUB 2 command line for the Linux operating system. Configure the default Grub2 kernel command line to contain audit=1 as follows:
# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) audit=1"
Each process on the system carries an "auditable" flag which indicates whether its activities can be audited. Although auditd takes care of enabling this for all processes which launch after it does, adding the kernel argument ensures it is set for every process during boot.
CCE-93872-0 Ensure the audit-libs package as a part of audit Subsystem is Installed The audit-libs package should be installed. The auditd service is an access monitoring and accounting daemon, watching system calls to audit any access, in comparison with potential local access control policy such as SELinux policy.
CCE-93874-6 Remove the X Windows Package Group By removing the xorg-x11-server-common package, the system no longer has X Windows installed. If X Windows is not installed then the system cannot boot into graphical user mode. This prevents the system from being accidentally or maliciously booted into a graphical.target mode. To do so, run the following command:
$ sudo zypper groupremove "X Window System"
$ sudo zypper remove xorg-x11-server-common
Unnecessary service packages must not be installed to decrease the attack surface of the system. X windows has a long history of security vulnerabilities and should not be installed unless approved and documented.
CCE-93875-3 Use Only Strong MACs Limit the MACs to strong hash algorithms. The following line in /etc/ssh/sshd_config demonstrates use of those MACs:
MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,hmac-ripemd160
MD5 and 96-bit MAC algorithms are considered weak and have been shown to increase exploitability in SSH downgrade attacks. Weak algorithms continue to have a great deal of attention as a weak spot that can be exploited with expanded computing power. An attacker that breaks the algorithm could take advantage of a MiTM position to decrypt the SSH tunnel and capture credentials and information
CCE-93876-1 Use Only Strong Key Exchange algorithms Limit the Key Exchange to strong algorithms. The following line in /etc/ssh/sshd_config demonstrates use of those:
KexAlgorithms ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256
Key exchange is any method in cryptography by which cryptographic keys are exchanged between two parties, allowing use of a cryptographic algorithm. If the sender and receiver wish to exchange encrypted messages, each must be equipped to encrypt messages to be sent and decrypt messages received
CCE-93877-9 Use Only Strong Ciphers Limit the ciphers to strong algorithms. Counter (CTR) mode is also preferred over cipher-block chaining (CBC) mode. The following line in /etc/ssh/sshd_config demonstrates use of those ciphers:
Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
The man page sshd_config(5) contains a list of supported ciphers.
Based on research conducted at various institutions, it was determined that the symmetric portion of the SSH Transport Protocol (as described in RFC 4253) has security weaknesses that allowed recovery of up to 32 bits of plaintext from a block of ciphertext that was encrypted with the Cipher Block Chaining (CBD) method. From that research, new Counter mode algorithms (as described in RFC4344) were designed that are not vulnerable to these types of attacks and these algorithms are now recommended for standard use.
CCE-93878-7 Ensure SSH MaxStartups is configured The MaxStartups parameter specifies the maximum number of concurrent unauthenticated connections to the SSH daemon. Additional connections will be dropped until authentication succeeds or the LoginGraceTime expires for a connection. To configure MaxStartups, you should add or edit the following line in the /etc/ssh/sshd_config file:
MaxStartups 10:30:100
To protect a system from denial of service due to a large number of pending authentication connection attempts, use the rate limiting function of MaxStartups to protect availability of sshd logins and prevent overwhelming the daemon.
CCE-93879-5 Set SSH MaxSessions limit The MaxSessions parameter specifies the maximum number of open sessions permitted from a given connection. To set MaxSessions edit /etc/ssh/sshd_config as follows:
MaxSessions 10
To protect a system from denial of service due to a large number of concurrent sessions, use the rate limiting function of MaxSessions to protect availability of sshd logins and prevent overwhelming the daemon.
CCE-93880-3 Set SSH authentication attempt limit The MaxAuthTries parameter specifies the maximum number of authentication attempts permitted per connection. Once the number of failures reaches half this value, additional failures are logged. to set MaxAUthTries edit /etc/ssh/sshd_config as follows:
MaxAuthTries 4
Setting the MaxAuthTries parameter to a low number will minimize the risk of successful brute force attacks to the SSH server.
CCE-93881-1 Ensure SSH LoginGraceTime is configured The LoginGraceTime parameter to the SSH server specifies the time allowed for successful authentication to the SSH server. The longer the Grace period is the more open unauthenticated connections can exist. Like other session controls in this session the Grace Period should be limited to appropriate limits to ensure the service is available for needed access. Setting the LoginGraceTime parameter to a low number will minimize the risk of successful brute force attacks to the SSH server. It will also limit the number of concurrent unauthenticated connections.
CCE-93882-9 Limit Users' SSH Access By default, the SSH configuration allows any user with an account to access the system. There are several options available to limit which users and group can access the system via SSH. It is recommended that at least one of the following options be leveraged: - AllowUsers variable gives the system administrator the option of allowing specific users to ssh into the system. The list consists of space separated user names. Numeric user IDs are not recognized with this variable. If a system administrator wants to restrict user access further by specifically allowing a user's access only from a particular host, the entry can be specified in the form of user@host. - AllowGroups variable gives the system administrator the option of allowing specific groups of users to ssh into the system. The list consists of space separated group names. Numeric group IDs are not recognized with this variable. - DenyUsers variable gives the system administrator the option of denying specific users to ssh into the system. The list consists of space separated user names. Numeric user IDs are not recognized with this variable. If a system administrator wants to restrict user access further by specifically denying a user's access from a particular host, the entry can be specified in the form of user@host. - DenyGroups variable gives the system administrator the option of denying specific groups of users to ssh into the system. The list consists of space separated group names. Numeric group IDs are not recognized with this variable. Specifying which accounts are allowed SSH access into the system reduces the possibility of unauthorized access to the system.
CCE-93883-7 Enable PAM UsePAM Enables the Pluggable Authentication Module interface. If set to “yes” this will enable PAM authentication using ChallengeResponseAuthentication and PasswordAuthentication in addition to PAM account and session module processing for all authentication types. To enable PAM authentication, add or correct the following line in /etc/ssh/sshd_config:
UsePAM yes
When UsePAM is set to yes, PAM runs through account and session types properly. This is important if you want to restrict access to services based off of IP, time or other factors of the account. Additionally, you can make sure users inherit certain environment variables on login or disallow access to the server.
CCE-93884-5 Disable SSH TCP Forwarding The AllowTcpForwarding parameter specifies whether TCP forwarding is permitted. To disable TCP forwarding, add or correct the following line in /etc/ssh/sshd_config:
AllowTcpForwarding no
Leaving port forwarding enabled can expose the organization to security risks and back-doors.
CCE-93885-2 Disable SSH Support for .rhosts Files SSH can emulate the behavior of the obsolete rsh command in allowing users to enable insecure access to their accounts via .rhosts files.
The default SSH configuration disables support for .rhosts. The appropriate configuration is used if no value is set for IgnoreRhosts.
To explicitly disable support for .rhosts files, add or correct the following line in /etc/ssh/sshd_config:
IgnoreRhosts yes
SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.
CCE-93886-0 Disable Host-Based Authentication SSH's cryptographic host-based authentication is more secure than .rhosts authentication. However, it is not recommended that hosts unilaterally trust one another, even within an organization.
The default SSH configuration disables host-based authentication. The appropriate configuration is used if no value is set for HostbasedAuthentication.
To explicitly disable host-based authentication, add or correct the following line in /etc/ssh/sshd_config:
HostbasedAuthentication no
SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.
CCE-93887-8 Verify Permissions on SSH Server config file To properly set the permissions of /etc/ssh/sshd_config, run the command:
$ sudo chmod 0600 /etc/ssh/sshd_config
Service configuration files enable or disable features of their respective services that if configured incorrectly can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the correct group to prevent unauthorized changes.
CCE-93888-6 Verify Owner on SSH Server config file To properly set the owner of /etc/ssh/sshd_config, run the command:
$ sudo chown root /etc/ssh/sshd_config 
Service configuration files enable or disable features of their respective services that if configured incorrectly can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the correct group to prevent unauthorized changes.
CCE-93889-4 Verify Group Who Owns SSH Server config file To properly set the group owner of /etc/ssh/sshd_config, run the command:
$ sudo chgrp root /etc/ssh/sshd_config
Service configuration files enable or disable features of their respective services that if configured incorrectly can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the correct group to prevent unauthorized changes.
CCE-93890-2 Disable snmpd Service The snmpd service can be disabled with the following command:
$ sudo systemctl mask --now snmpd.service
Running SNMP software provides a network-based avenue of attack, and should be disabled if not needed.
CCE-93891-0 Uninstall net-snmp Package The net-snmp package provides the snmpd service. The net-snmp package can be removed with the following command:
$ sudo zypper remove net-snmp
If there is no need to run SNMP server software, removing the package provides a safeguard against its activation.
CCE-93892-8 Disable Samba The smb service can be disabled with the following command:
$ sudo systemctl mask --now smb.service
Running a Samba server provides a network-based avenue of attack, and should be disabled if not needed.
CCE-93893-6 Uninstall Samba Package The samba package can be removed with the following command:
 $ sudo zypper remove samba
If there is no need to make the Samba software available, removing it provides a safeguard against its activation.
CCE-93894-4 Disable Squid The squid service can be disabled with the following command:
$ sudo systemctl mask --now squid.service
Running proxy server software provides a network-based avenue of attack, and should be removed if not needed.
CCE-93895-1 Uninstall squid Package The squid package can be removed with the following command:
 $ sudo zypper remove squid
If there is no need to make the proxy server software available, removing it provides a safeguard against its activation.
CCE-93896-9 Disable the CUPS Service The cups service can be disabled with the following command:
$ sudo systemctl mask --now cups.service
Turn off unneeded services to reduce attack surface.
CCE-93897-7 Uninstall CUPS Package The cups package can be removed with the following command:
$ sudo zypper remove cups
If the system does not need to print jobs or accept print jobs from other systems, it is recommended that CUPS be removed to reduce the potential attack surface.
CCE-93898-5 Remove telnet Clients The telnet client allows users to start connections to other systems via the telnet protocol. The telnet protocol is insecure and unencrypted. The use of an unencrypted transmission medium could allow an unauthorized user to steal credentials. The ssh package provides an encrypted session and stronger security and is included in SUSE Linux Enterprise Micro 5.
CCE-93899-3 Uninstall telnet-server Package The telnet-server package can be removed with the following command:
$ sudo zypper remove telnet-server
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities are often overlooked and therefore may remain insecure. They increase the risk to the platform by providing additional attack vectors.
The telnet service provides an unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to login using this service, the privileged user password could be compromised.
Removing the telnet-server package decreases the risk of the telnet service's accidental (or intentional) activation.
CCE-93900-9 Uninstall talk Package The talk package contains the client program for the Internet talk protocol, which allows the user to chat with other users on different systems. Talk is a communication program which copies lines from one terminal to the terminal of another user. The talk package can be removed with the following command:
$ sudo zypper remove talk
The talk software presents a security risk as it uses unencrypted protocols for communications. Removing the talk package decreases the risk of the accidental (or intentional) activation of talk client program.
CCE-93901-7 Uninstall rsh Package The rsh package contains the client commands for the rsh services These legacy clients contain numerous security exposures and have been replaced with the more secure SSH package. Even if the server is removed, it is best to ensure the clients are also removed to prevent users from inadvertently attempting to use these commands and therefore exposing their credentials. Note that removing the rsh package removes the clients for rsh,rcp, and rlogin.
CCE-93902-5 Uninstall ypserv Package The ypserv package can be removed with the following command:
$ sudo zypper remove ypserv
The NIS service provides an unencrypted authentication service which does not provide for the confidentiality and integrity of user passwords or the remote session. Removing the ypserv package decreases the risk of the accidental (or intentional) activation of NIS or NIS+ services.
CCE-93903-3 Remove NIS Client The Network Information Service (NIS), formerly known as Yellow Pages, is a client-server directory service protocol used to distribute system configuration files. The NIS client (ypbind) was used to bind a system to an NIS server and receive the distributed configuration files. The NIS service is inherently an insecure system that has been vulnerable to DOS attacks, buffer overflows and has poor authentication for querying NIS maps. NIS generally has been replaced by such protocols as Lightweight Directory Access Protocol (LDAP). It is recommended that the service be removed.
CCE-93904-1 Disable xinetd Service The xinetd service can be disabled with the following command:
$ sudo systemctl mask --now xinetd.service
The xinetd service provides a dedicated listener service for some programs, which is no longer necessary for commonly-used network services. Disabling it ensures that these uncommon services are not running, and also prevents attacks against xinetd itself.
CCE-93905-8 Uninstall xinetd Package The xinetd package can be removed with the following command:
$ sudo zypper remove xinetd
Removing the xinetd package decreases the risk of the xinetd service's accidental (or intentional) activation.
CCE-93906-6 Uninstall tcpd Package The tcpd package can be removed with the following command:
$ sudo zypper remove tcpd
Administrators can use TCP wrapper library and daemon for host control over network services. In these implementations, xinetd runs tcpd program, which first looks at the incoming connection as well as the access control lists in the /etc/hosts.allow and /etc/hosts.deny files. Removing the xinetd package decreases the risk of the xinetd service's accidental (or intentional) activation. The removal of tcpd package will support this protective measure in addition.
CCE-93907-4 Ensure that chronyd is running under chrony user account chrony is a daemon which implements the Network Time Protocol (NTP). It is designed to synchronize system clocks across a variety of systems and use a source that is highly accurate. More information on chrony can be found at https://chrony-project.org/. Chrony can be configured to be a client and/or a server. To ensure that chronyd is running under chrony user account, add or edit the OPTIONS variable in /etc/sysconfig/chronyd to include -u chrony:
OPTIONS="-u chrony"
This recommendation only applies if chrony is in use on the system.
If chrony is in use on the system proper configuration is vital to ensuring time synchronization is working properly.
CCE-93908-2 Chrony Configure Pool and Server Chrony is a daemon which implements the Network Time Protocol (NTP). It is designed to synchronize system clocks across a variety of systems and use a source that is highly accurate. More information on chrony can be found at https://chrony-project.org/. Chrony can be configured to be a client and/or a server. Add or edit server or pool lines to /etc/chrony.conf as appropriate:
server <remote-server>
Multiple servers may be configured.
If chrony is in use on the system proper configuration is vital to ensuring time synchronization is working properly.
CCE-93909-0 The Chrony package is installed System time should be synchronized between all systems in an environment. This is typically done by establishing an authoritative time server or set of servers and having all systems synchronize their clocks to them. The chrony package can be installed with the following command:
$ sudo zypper install chrony
Time synchronization is important to support time sensitive security mechanisms like Kerberos and also ensures log files have consistent time records across the enterprise, which aids in forensic investigations.
CCE-93910-8 Disable Network File System (nfs) The Network File System (NFS) service allows remote hosts to mount and interact with shared filesystems on the local system. If the local system is not designated as a NFS server then this service should be disabled. The nfs-server service can be disabled with the following command:
$ sudo systemctl mask --now nfs-server.service
Unnecessary services should be disabled to decrease the attack surface of the system.
CCE-93911-6 Uninstall nfs-utils Package The nfs-utils package can be removed with the following command:
$ sudo zypper remove nfs-utils
nfs-utils provides a daemon for the kernel NFS server and related tools. This package also contains the showmount program. showmount queries the mount daemon on a remote host for information about the Network File System (NFS) server on the remote host. For example, showmount can display the clients which are mounted on that host.
CCE-93912-4 Disable Postfix Network Listening Edit the file /etc/postfix/main.cf to ensure that only the following inet_interfaces line appears:
inet_interfaces = loopback-only
This ensures postfix accepts mail messages (such as cron job reports) from the local system only, and not from the network, which protects it from network attack.
CCE-93913-2 Uninstall openldap-servers Package The openldap-servers package is not installed by default on a SUSE Linux Enterprise Micro 5 system. It is needed only by the OpenLDAP server, not by the clients which use LDAP for authentication. If the system is not intended for use as an LDAP Server it should be removed. Unnecessary packages should not be installed to decrease the attack surface of the system. While this software is clearly essential on an LDAP server, it is not necessary on typical desktop or workstation systems.
CCE-93914-0 Ensure LDAP client is not installed The Lightweight Directory Access Protocol (LDAP) is a service that provides a method for looking up information from a central database. The openldap-clients package can be removed with the following command:
$ sudo zypper remove openldap-clients
If the system does not need to act as an LDAP client, it is recommended that the software is removed to reduce the potential attack surface.
CCE-93915-7 Disable Dovecot Service The dovecot service can be disabled with the following command:
$ sudo systemctl mask --now dovecot.service
Running an IMAP or POP3 server provides a network-based avenue of attack, and should be disabled if not needed.
CCE-93916-5 Uninstall dovecot Package The dovecot package can be removed with the following command:
$ sudo zypper remove dovecot
If there is no need to make the Dovecot software available, removing it provides a safeguard against its activation.
CCE-93917-3 Disable httpd Service The httpd service can be disabled with the following command:
$ sudo systemctl mask --now httpd.service
Running web server software provides a network-based avenue of attack, and should be disabled if not needed.
CCE-93918-1 Uninstall httpd Package The httpd package can be removed with the following command:
$ sudo zypper remove httpd
If there is no need to make the web server software available, removing it provides a safeguard against its activation.
CCE-93919-9 Disable vsftpd Service The vsftpd service can be disabled with the following command:
$ sudo systemctl mask --now vsftpd.service
Running FTP server software provides a network-based avenue of attack, and should be disabled if not needed. Furthermore, the FTP protocol is unencrypted and creates a risk of compromising sensitive information.
CCE-93920-7 Uninstall vsftpd Package The vsftpd package can be removed with the following command:
 $ sudo zypper remove vsftpd
Removing the vsftpd package decreases the risk of its accidental activation.
CCE-93921-5 Disable named Service The named service can be disabled with the following command:
$ sudo systemctl mask --now named.service
All network services involve some risk of compromise due to implementation flaws and should be disabled if possible.
CCE-93922-3 Uninstall bind Package The named service is provided by the bind package. The bind package can be removed with the following command:
$ sudo zypper remove bind
If there is no need to make DNS server software available, removing it provides a safeguard against its activation.
CCE-93923-1 Disable DHCP Service The dhcpd service should be disabled on any system that does not need to act as a DHCP server. The dhcpd service can be disabled with the following command:
$ sudo systemctl mask --now dhcpd.service
Unmanaged or unintentionally activated DHCP servers may provide faulty information to clients, interfering with the operation of a legitimate site DHCP server if there is one.
CCE-93924-9 Uninstall DHCP Server Package If the system does not need to act as a DHCP server, the dhcp package can be uninstalled. The dhcp package can be removed with the following command:
$ sudo zypper remove dhcp
Removing the DHCP server ensures that it cannot be easily or accidentally reactivated and disrupt network operation.
CCE-93925-6 Uninstall DHCP Client Package If the system does not need to act as a DHCP client, the dhcp-client package can be uninstalled. The dhcp-client package can be removed with the following command:
$ sudo zypper remove dhcp-client
Removing the DHCP client is necessary when the system works or will work in a static network environment. In this case the system has/will have a static IP address assigned.
CCE-93926-4 Verify Permissions on /etc/at.allow file If /etc/at.allow exists, it must have permissions 0640 or more restrictive. To properly set the permissions of /etc/at.allow, run the command:
$ sudo chmod 0640 /etc/at.allow
If the permissions of the at.allow file are not set to 0640 or more restrictive, the possibility exists for an unauthorized user to view or edit sensitive information.
CCE-93927-2 Verify User Who Owns /etc/at.allow file If /etc/at.allow exists, it must be owned by root. To properly set the owner of /etc/at.allow, run the command:
$ sudo chown root /etc/at.allow 
If the owner of the at.allow file is not set to root, the possibility exists for an unauthorized user to view or edit sensitive information.
CCE-93928-0 Verify Group Who Owns /etc/at.allow file If /etc/at.allow exists, it must be group-owned by root. To properly set the group owner of /etc/at.allow, run the command:
$ sudo chgrp root /etc/at.allow
If the owner of the at.allow file is not set to root, the possibility exists for an unauthorized user to view or edit sensitive information.
CCE-93929-8 Ensure that /etc/at.deny does not exist The file /etc/at.deny should not exist. Use /etc/at.allow instead. Access to at should be restricted. It is easier to manage an allow list than a deny list.
CCE-93930-6 Disable Avahi Server Software The avahi-daemon service can be disabled with the following command:
$ sudo systemctl mask --now avahi-daemon.service
Because the Avahi daemon service keeps an open network port, it is subject to network attacks. Its functionality is convenient but is only appropriate if the local network can be trusted.
CCE-93931-4 Uninstall avahi Server Package If the system does not need to have an Avahi server which implements the DNS Service Discovery and Multicast DNS protocols, the avahi-autoipd and avahi packages can be uninstalled. Automatic discovery of network services is not normally required for system functionality. It is recommended to remove this package to reduce the potential attack surface.
CCE-93932-2 Uninstall avahi-autoipd Server Package If the system does not need to have an Avahi server which implements the DNS Service Discovery and Multicast DNS protocols, the avahi-autoipd and avahi packages can be uninstalled. Automatic discovery of network services is not normally required for system functionality. It is recommended to remove this package to reduce the potential attack surface.
CCE-93933-0 Install PAE Kernel on Supported 32-bit x86 Systems Systems that are using the 64-bit x86 kernel package do not need to install the kernel-PAE package because the 64-bit x86 kernel already includes this support. However, if the system is 32-bit and also supports the PAE and NX features as determined in the previous section, the kernel-PAE package should be installed to enable XD or NX support. The kernel-PAE package can be installed with the following command:
$ sudo zypper install kernel-PAE
The installation process should also have configured the bootloader to load the new kernel at boot. Verify this after reboot and modify /etc/default/grub if necessary.
On 32-bit systems that support the XD or NX bit, the vendor-supplied PAE kernel is required to enable either Execute Disable (XD) or No Execute (NX) support.
CCE-93934-8 Enable NX or XD Support in the BIOS Reboot the system and enter the BIOS or Setup configuration menu. Navigate the BIOS configuration menu and make sure that the option is enabled. The setting may be located under a Security section. Look for Execute Disable (XD) on Intel-based systems and No Execute (NX) on AMD-based systems. Computers with the ability to prevent this type of code execution frequently put an option in the BIOS that will allow users to turn the feature on or off at will.
CCE-93935-5 Disable Core Dumps for SUID programs To set the runtime status of the fs.suid_dumpable kernel parameter, run the following command:
$ sudo sysctl -w fs.suid_dumpable=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
fs.suid_dumpable = 0
The core dump of a setuid program is more likely to contain sensitive data, as the program itself runs with greater privileges than the user who initiated execution of the program. Disabling the ability for any setuid program to write a core file decreases the risk of unauthorized access of such data.
CCE-93936-3 Disable Core Dumps for All Users To disable core dumps for all users, add the following line to /etc/security/limits.conf, or to a file within the /etc/security/limits.d/ directory:
*     hard   core    0
A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers trying to debug problems.
CCE-93937-1 Disable storing core dump The Storage option in [Coredump] section of /etc/systemd/coredump.conf or a drop-in file in /etc/systemd/coredump.conf.d/*.conf can be set to none to disable storing core dumps permanently. A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers or system operators trying to debug problems. Enabling core dumps on production systems is not recommended, however there may be overriding operational requirements to enable advanced debugging. Permitting temporary enablement of core dumps during such situations should be reviewed through local needs and policy.
CCE-93938-9 Disable core dump backtraces The ProcessSizeMax option in [Coredump] section of /etc/systemd/coredump.conf or in a drop-in file under /etc/systemd/coredump.conf.d/ specifies the maximum size in bytes of a core which will be processed. Core dumps exceeding this size may be stored, but the backtrace will not be generated. A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers or system operators trying to debug problems. Enabling core dumps on production systems is not recommended, however there may be overriding operational requirements to enable advanced debugging. Permitting temporary enablement of core dumps during such situations should be reviewed through local needs and policy.
CCE-93939-7 Add noexec Option to Removable Media Partitions The noexec mount option prevents the direct execution of binaries on the mounted filesystem. Preventing the direct execution of binaries from removable media (such as a USB key) provides a defense against malicious software that may be present on such untrusted media. Add the noexec option to the fourth column of /etc/fstab for the line which controls mounting of any removable media partitions. Allowing users to execute binaries from removable media such as USB keys exposes the system to potential compromise.
CCE-93940-5 Add nodev Option to Removable Media Partitions The nodev mount option prevents files from being interpreted as character or block devices. Legitimate character and block devices should exist only in the /dev directory on the root partition or within chroot jails built for system services. Add the nodev option to the fourth column of /etc/fstab for the line which controls mounting of any removable media partitions. The only legitimate location for device files is the /dev directory located on the root partition. An exception to this is chroot jails, and it is not advised to set nodev on partitions which contain their root filesystems.
CCE-93941-3 Add nodev Option to /home The nodev mount option can be used to prevent device files from being created in /home. Legitimate character and block devices should exist only in the /dev directory on the root partition or within chroot jails built for system services. Add the nodev option to the fourth column of /etc/fstab for the line which controls mounting of /home. The only legitimate location for device files is the /dev directory located on the root partition. The only exception to this is chroot jails.
CCE-93942-1 Add nosuid Option to /dev/shm The nosuid mount option can be used to prevent execution of setuid programs in /dev/shm. The SUID and SGID permissions should not be required in these world-writable directories. Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of /dev/shm. The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from temporary storage partitions.
CCE-93943-9 Add noexec Option to /dev/shm The noexec mount option can be used to prevent binaries from being executed out of /dev/shm. It can be dangerous to allow the execution of binaries from world-writable temporary storage directories such as /dev/shm. Add the noexec option to the fourth column of /etc/fstab for the line which controls mounting of /dev/shm. Allowing users to execute binaries from world-writable directories such as /dev/shm can expose the system to potential compromise.
CCE-93944-7 Add nodev Option to /dev/shm The nodev mount option can be used to prevent creation of device files in /dev/shm. Legitimate character and block devices should not exist within temporary directories like /dev/shm. Add the nodev option to the fourth column of /etc/fstab for the line which controls mounting of /dev/shm. The only legitimate location for device files is the /dev directory located on the root partition. The only exception to this is chroot jails.
CCE-93945-4 Disable Mounting of vFAT filesystems To configure the system to prevent the vfat kernel module from being loaded, add the following line to the file /etc/modprobe.d/vfat.conf:
install vfat /bin/false
This entry will cause a non-zero return value during a vfat module installation and additionally convey the meaning of the entry to the user in form of an error message. If you would like to omit a non-zero return value and an error message, you may want to add a different line instead (both /bin/true and /bin/false are allowed by OVAL and will be accepted by the scan):
install vfat /bin/true
This effectively prevents usage of this uncommon filesystem. The vFAT filesystem format is primarily used on older windows systems and portable USB drives or flash modules. It comes in three types FAT12, FAT16, and FAT32 all of which are supported by the vfat kernel module.
Removing support for unneeded filesystems reduces the local attack surface of the system.
CCE-93946-2 Disable Mounting of udf To configure the system to prevent the udf kernel module from being loaded, add the following line to the file /etc/modprobe.d/udf.conf:
install udf /bin/false
This entry will cause a non-zero return value during a udf module installation and additionally convey the meaning of the entry to the user in form of an error message. If you would like to omit a non-zero return value and an error message, you may want to add a different line instead (both /bin/true and /bin/false are allowed by OVAL and will be accepted by the scan):
install udf /bin/true
This effectively prevents usage of this uncommon filesystem. The udf filesystem type is the universal disk format used to implement the ISO/IEC 13346 and ECMA-167 specifications. This is an open vendor filesystem type for data storage on a broad range of media. This filesystem type is necessary to support writing DVDs and newer optical disc formats.
Removing support for unneeded filesystem types reduces the local attack surface of the system.
CCE-93947-0 Disable Mounting of squashfs To configure the system to prevent the squashfs kernel module from being loaded, add the following line to the file /etc/modprobe.d/squashfs.conf:
install squashfs /bin/false
This entry will cause a non-zero return value during a squashfs module installation and additionally convey the meaning of the entry to the user in form of an error message. If you would like to omit a non-zero return value and an error message, you may want to add a different line instead (both /bin/true and /bin/false are allowed by OVAL and will be accepted by the scan):
install squashfs /bin/true
This effectively prevents usage of this uncommon filesystem. The squashfs filesystem type is a compressed read-only Linux filesystem embedded in small footprint systems (similar to cramfs). A squashfs image can be used without having to first decompress the image.
Removing support for unneeded filesystem types reduces the local attack surface of the system.
CCE-93948-8 Disable Mounting of cramfs To configure the system to prevent the cramfs kernel module from being loaded, add the following line to the file /etc/modprobe.d/cramfs.conf:
install cramfs /bin/false
This entry will cause a non-zero return value during a cramfs module installation and additionally convey the meaning of the entry to the user in form of an error message. If you would like to omit a non-zero return value and an error message, you may want to add a different line instead (both /bin/true and /bin/false are allowed by OVAL and will be accepted by the scan):
install cramfs /bin/true
This effectively prevents usage of this uncommon filesystem. The cramfs filesystem type is a compressed read-only Linux filesystem embedded in small footprint systems. A cramfs image can be used without having to first decompress the image.
Removing support for unneeded filesystem types reduces the local attack surface of the server.
CCE-93949-6 Verify Permissions on shadow File To properly set the permissions of /etc/shadow, run the command:
$ sudo chmod 0000 /etc/shadow
The /etc/shadow file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.
CCE-93950-4 Verify Permissions on passwd File To properly set the permissions of /etc/passwd, run the command:
$ sudo chmod 0644 /etc/passwd
If the /etc/passwd file is writable by a group-owner or the world the risk of its compromise is increased. The file contains the list of accounts on the system and associated information, and protection of this file is critical for system security.
CCE-93951-2 Verify Permissions on gshadow File To properly set the permissions of /etc/gshadow, run the command:
$ sudo chmod 0000 /etc/gshadow
The /etc/gshadow file contains group password hashes. Protection of this file is critical for system security.
CCE-93952-0 Verify Permissions on group File To properly set the permissions of /etc/group, run the command:
$ sudo chmod 0644 /etc/group
The /etc/group file contains information regarding groups that are configured on the system. Protection of this file is important for system security.
CCE-93953-8 Verify Permissions on Backup shadow File To properly set the permissions of /etc/shadow-, run the command:
$ sudo chmod 0000 /etc/shadow-
The /etc/shadow- file is a backup file of /etc/shadow, and as such, it contains the list of local system accounts and password hashes. Protection of this file is critical for system security.
CCE-93954-6 Verify Permissions on Backup passwd File To properly set the permissions of /etc/passwd-, run the command:
$ sudo chmod 0644 /etc/passwd-
The /etc/passwd- file is a backup file of /etc/passwd, and as such, it contains information about the users that are configured on the system. Protection of this file is critical for system security.
CCE-93955-3 Verify Permissions on Backup gshadow File To properly set the permissions of /etc/gshadow-, run the command:
$ sudo chmod 0000 /etc/gshadow-
The /etc/gshadow- file is a backup of /etc/gshadow, and as such, it contains group password hashes. Protection of this file is critical for system security.
CCE-93956-1 Verify Permissions on Backup group File To properly set the permissions of /etc/group-, run the command:
$ sudo chmod 0644 /etc/group-
The /etc/group- file is a backup file of /etc/group, and as such, it contains information regarding groups that are configured on the system. Protection of this file is important for system security.
CCE-93957-9 Verify User Who Owns shadow File To properly set the owner of /etc/shadow, run the command:
$ sudo chown root /etc/shadow 
The /etc/shadow file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.
CCE-93958-7 Verify User Who Owns passwd File To properly set the owner of /etc/passwd, run the command:
$ sudo chown root /etc/passwd 
The /etc/passwd file contains information about the users that are configured on the system. Protection of this file is critical for system security.
CCE-93959-5 Verify User Who Owns gshadow File To properly set the owner of /etc/gshadow, run the command:
$ sudo chown root /etc/gshadow 
The /etc/gshadow file contains group password hashes. Protection of this file is critical for system security.
CCE-93960-3 Verify User Who Owns group File To properly set the owner of /etc/group, run the command:
$ sudo chown root /etc/group 
The /etc/group file contains information regarding groups that are configured on the system. Protection of this file is important for system security.
CCE-93961-1 Verify Group Who Owns Backup shadow File To properly set the owner of /etc/shadow-, run the command:
$ sudo chown root /etc/shadow- 
The /etc/shadow- file is a backup file of /etc/shadow, and as such, it contains the list of local system accounts and password hashes. Protection of this file is critical for system security.
CCE-93962-9 Verify User Who Owns Backup passwd File To properly set the owner of /etc/passwd-, run the command:
$ sudo chown root /etc/passwd- 
The /etc/passwd- file is a backup file of /etc/passwd, and as such, it contains information about the users that are configured on the system. Protection of this file is critical for system security.
CCE-93963-7 Verify User Who Owns Backup gshadow File To properly set the owner of /etc/gshadow-, run the command:
$ sudo chown root /etc/gshadow- 
The /etc/gshadow- file is a backup of /etc/gshadow, and as such, it contains group password hashes. Protection of this file is critical for system security.
CCE-93964-5 Verify User Who Owns Backup group File To properly set the owner of /etc/group-, run the command:
$ sudo chown root /etc/group- 
The /etc/group- file is a backup file of /etc/group, and as such, it contains information regarding groups that are configured on the system. Protection of this file is important for system security.
CCE-93965-2 Verify Group Who Owns shadow File To properly set the group owner of /etc/shadow, run the command:
$ sudo chgrp root /etc/shadow
The /etc/shadow file stores password hashes. Protection of this file is critical for system security.
CCE-93966-0 Verify Group Who Owns passwd File To properly set the group owner of /etc/passwd, run the command:
$ sudo chgrp root /etc/passwd
The /etc/passwd file contains information about the users that are configured on the system. Protection of this file is critical for system security.
CCE-93967-8 Verify Group Who Owns gshadow File To properly set the group owner of /etc/gshadow, run the command:
$ sudo chgrp root /etc/gshadow
The /etc/gshadow file contains group password hashes. Protection of this file is critical for system security.
CCE-93968-6 Verify Group Who Owns group File To properly set the group owner of /etc/group, run the command:
$ sudo chgrp root /etc/group
The /etc/group file contains information regarding groups that are configured on the system. Protection of this file is important for system security.
CCE-93969-4 Verify User Who Owns Backup shadow File To properly set the group owner of /etc/shadow-, run the command:
$ sudo chgrp root /etc/shadow-
The /etc/shadow- file is a backup file of /etc/shadow, and as such, it contains the list of local system accounts and password hashes. Protection of this file is critical for system security.
CCE-93970-2 Verify Group Who Owns Backup passwd File To properly set the group owner of /etc/passwd-, run the command:
$ sudo chgrp root /etc/passwd-
The /etc/passwd- file is a backup file of /etc/passwd, and as such, it contains information about the users that are configured on the system. Protection of this file is critical for system security.
CCE-93971-0 Verify Group Who Owns Backup gshadow File To properly set the group owner of /etc/gshadow-, run the command:
$ sudo chgrp root /etc/gshadow-
The /etc/gshadow- file is a backup of /etc/gshadow, and as such, it contains group password hashes. Protection of this file is critical for system security.
CCE-93972-8 Verify Group Who Owns Backup group File To properly set the group owner of /etc/group-, run the command:
$ sudo chgrp root /etc/group-
The /etc/group- file is a backup file of /etc/group, and as such, it contains information regarding groups that are configured on the system. Protection of this file is important for system security.
CCE-93973-6 Ensure No World-Writable Files Exist It is generally a good idea to remove global (other) write access to a file when it is discovered. However, check with documentation for specific applications before making changes. Also, monitor for recurring world-writable files, as these may be symptoms of a misconfigured application or user account. Finally, this applies to real files and not virtual files that are a part of pseudo file systems such as sysfs or procfs. Data in world-writable files can be modified by any user on the system. In almost all circumstances, files can be configured using a combination of user and group permissions to support whatever legitimate access is needed without the risk caused by world-writable files.
CCE-93974-4 Disable SCTP Support The Stream Control Transmission Protocol (SCTP) is a transport layer protocol, designed to support the idea of message-oriented communication, with several streams of messages within one connection. To configure the system to prevent the sctp kernel module from being loaded, add the following line to the file /etc/modprobe.d/sctp.conf:
install sctp /bin/false
This entry will cause a non-zero return value during a sctp module installation and additionally convey the meaning of the entry to the user in form of an error message. If you would like to omit a non-zero return value and an error message, you may want to add a different line instead (both /bin/true and /bin/false are allowed by OVAL and will be accepted by the scan):
install sctp /bin/true
Disabling SCTP protects the system against exploitation of any flaws in its implementation.
CCE-93975-1 Disable DCCP Support The Datagram Congestion Control Protocol (DCCP) is a relatively new transport layer protocol, designed to support streaming media and telephony. To configure the system to prevent the dccp kernel module from being loaded, add the following line to the file /etc/modprobe.d/dccp.conf:
install dccp /bin/false
This entry will cause a non-zero return value during a dccp module installation and additionally convey the meaning of the entry to the user in form of an error message. If you would like to omit a non-zero return value and an error message, you may want to add a different line instead (both /bin/true and /bin/false are allowed by OVAL and will be accepted by the scan):
install dccp /bin/true
Disabling DCCP protects the system against exploitation of any flaws in its implementation.
CCE-93976-9 Ensure a Table Exists for Nftables Tables in nftables hold chains. Each table only has one address family and only applies to packets of this family. Tables can have one of six families. Nftables doesn't have any default tables. Without a table being built, nftables will not filter network traffic.
CCE-93977-7 Ensure all outbound and established connections are configured for nftables Configure the nftables firewall rules for new outbound and established connections If rules are not in place for new outbound and established connections, all packets will be dropped by the default policy preventing network usage.
CCE-93978-5 Set nftables Configuration for Loopback Traffic Configure the loopback interface to accept traffic. Configure all other interfaces to deny traffic to the loopback network. Loopback traffic is generated between processes on machine and is typically critical to operation of the system. The loopback interface is the only place that loopback network traffic should be seen, all other interfaces should ignore traffic on this network as an anti-spoofing measure.
CCE-93979-3 Ensure Base Chains Exist for Nftables Tables in nftables hold chains. Each table only has one address family and only applies to packets of this family. Tables can have one of six families. Chains are containers for rules. They exist in two kinds, base chains and regular chains. A base chain is an entry point for packets from the networking stack, a regular chain may be used as jump target and is used for better rule organization. If a base chain doesn't exist with a hook for input, forward, and delete, packets that would flow through those chains will not be touched by nftables.
CCE-93980-1 Ensure nftables Rules are Permanent nftables is a subsystem of the Linux kernel providing filtering and classification of network packets/datagrams/frames. The nftables service reads the /etc/sysconfig/nftables.conf file for a nftables file or files to include in the nftables ruleset. A nftables ruleset containing the input, forward, and output base chains allow network traffic to be filtered. Changes made to nftables ruleset only affect the live system, you will also need to configure the nftables ruleset to apply on boot
CCE-93981-9 Ensure nftables Default Deny Firewall Policy Base chain policy is the default verdict that will be applied to packets reaching the end of the chain. There are two policies: accept (Default) and drop. If the policy is set to accept, the firewall will accept any packet that is not configured to be denied and the packet will continue traversing the network stack. Run the following commands and verify that base chains contain a policy of DROP.
$ nft list ruleset | grep 'hook input'
type filter hook input priority 0; policy drop;
$ nft list ruleset | grep 'hook forward'
type filter hook forward priority 0; policy drop;
$ nft list ruleset | grep 'hook output'
type filter hook output priority 0; policy drop;
It is easier to allow acceptable usage than to block unacceptable usage.
CCE-93982-7 Verify nftables Service is Disabled nftables is a subsystem of the Linux kernel providing filtering and classification of network packets/datagrams/frames and is the successor to iptables. The nftables service can be disabled with the following command:
systemctl disable nftables
Running both firewalld and nftables may lead to conflict. nftables is actually one of the backends for firewalld management tools.
CCE-93983-5 Verify nftables Service is Enabled The nftables service allows for the loading of nftables rulesets during boot, or starting on the nftables service The nftables service can be enabled with the following command:
$ sudo systemctl enable nftables.service
The nftables service restores the nftables rules from the rules files referenced in the /etc/sysconfig/nftables.conf file during boot or the starting of the nftables service
CCE-93984-3 Uninstall nftables package nftables is a subsystem of the Linux kernel providing filtering and classification of network packets/datagrams/frames and is the successor to iptables. The nftables package can be removed with the following command:
$ sudo zypper remove nftables
Running both firewalld and nftables may lead to conflict.
CCE-93985-0 Install nftables Package nftables provides a new in-kernel packet classification framework that is based on a network-specific Virtual Machine (VM) and a new nft userspace command line tool. nftables reuses the existing Netfilter subsystems such as the existing hook infrastructure, the connection tracking system, NAT, userspace queuing and logging subsystem. The nftables package can be installed with the following command:
$ sudo zypper install nftables
nftables is a subsystem of the Linux kernel that can protect against threats originating from within a corporate network to include malicious mobile code and poorly configured software on a host.
CCE-93986-8 Enable Kernel Parameter to Ignore Bogus ICMP Error Responses on IPv4 Interfaces To set the runtime status of the net.ipv4.icmp_ignore_bogus_error_responses kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.icmp_ignore_bogus_error_responses = 1
Ignoring bogus ICMP error responses reduces log size, although some activity would not be logged.
CCE-93987-6 Enable Kernel Parameter to Ignore ICMP Broadcast Echo Requests on IPv4 Interfaces To set the runtime status of the net.ipv4.icmp_echo_ignore_broadcasts kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.icmp_echo_ignore_broadcasts = 1
Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks.
Ignoring ICMP echo requests (pings) sent to broadcast or multicast addresses makes the system slightly more difficult to enumerate on the network.
CCE-93988-4 Configure Kernel Parameter for Accepting Secure Redirects By Default To set the runtime status of the net.ipv4.conf.default.secure_redirects kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.default.secure_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.secure_redirects = 0
Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.
CCE-93989-2 Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces by Default To set the runtime status of the net.ipv4.conf.default.rp_filter kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.default.rp_filter=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.rp_filter = 1
Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.
CCE-93990-0 Enable Kernel Parameter to Log Martian Packets on all IPv4 Interfaces by Default To set the runtime status of the net.ipv4.conf.default.log_martians kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.default.log_martians=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.log_martians = 1
The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.
CCE-93991-8 Disable Kernel Parameter for Accepting Secure ICMP Redirects on all IPv4 Interfaces To set the runtime status of the net.ipv4.conf.all.secure_redirects kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.all.secure_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.secure_redirects = 0
Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.
CCE-93992-6 Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces To set the runtime status of the net.ipv4.conf.all.rp_filter kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.all.rp_filter=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.rp_filter = 1
Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.
CCE-93993-4 Enable Kernel Parameter to Log Martian Packets on all IPv4 Interfaces To set the runtime status of the net.ipv4.conf.all.log_martians kernel parameter, run the following command:
$ sudo sysctl -w net.ipv4.conf.all.log_martians=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.log_martians = 1
The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.
CCE-93994-2 Disable Accepting Router Advertisements on all IPv6 Interfaces by Default To set the runtime status of the net.ipv6.conf.default.accept_ra kernel parameter, run the following command:
$ sudo sysctl -w net.ipv6.conf.default.accept_ra=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.default.accept_ra = 0
An illicit router advertisement message could result in a man-in-the-middle attack.
CCE-93995-9 Configure Accepting Router Advertisements on All IPv6 Interfaces To set the runtime status of the net.ipv6.conf.all.accept_ra kernel parameter, run the following command:
$ sudo sysctl -w net.ipv6.conf.all.accept_ra=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.all.accept_ra = 0
An illicit router advertisement message could result in a man-in-the-middle attack.
CCE-93996-7 Disable IPv6 Addressing on All IPv6 Interfaces To disable support for (ipv6) addressing on all interface add the following line to /etc/sysctl.d/ipv6.conf (or another file in /etc/sysctl.d):
net.ipv6.conf.all.disable_ipv6 = 1
This disables IPv6 on all network interfaces as other services and system functionality require the IPv6 stack loaded to work.
Any unnecessary network stacks - including IPv6 - should be disabled, to reduce the vulnerability to exploitation.
CCE-93997-5 Ensure IPv6 is disabled through kernel boot parameter To disable IPv6 protocol support in the Linux kernel, add the argument ipv6.disable=1 to the default GRUB2 command line for the Linux operating system. Configure the default Grub2 kernel command line to contain ipv6.disable=1 as follows:
# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) ipv6.disable=1"
Any unnecessary network stacks, including IPv6, should be disabled to reduce the vulnerability to exploitation.
CCE-93998-3 Ensure Outbound and Established Connections are Configured Configure the firewall rules for new outbound and established connections. If rules are not in place for new outbound, and established connections all packets will be dropped by the default policy preventing network usage.
CCE-93999-1 Set Default iptables Policy for Forwarded Packets To set the default policy to DROP (instead of ACCEPT) for the built-in FORWARD chain which processes packets that will be forwarded from one interface to another, add or correct the following line in /etc/sysconfig/iptables:
:FORWARD DROP [0:0]
In iptables, the default policy is applied only after all the applicable rules in the table are examined for a match. Setting the default policy to DROP implements proper design for a firewall, i.e. any packets which are not explicitly permitted should not be accepted.
CCE-94000-7 Set Default iptables Policy for Incoming Packets To set the default policy to DROP (instead of ACCEPT) for the built-in INPUT chain which processes incoming packets, add or correct the following line in /etc/sysconfig/iptables:
:INPUT DROP [0:0]
In iptables the default policy is applied only after all the applicable rules in the table are examined for a match. Setting the default policy to DROP implements proper design for a firewall, i.e. any packets which are not explicitly permitted should not be accepted.
CCE-94001-5 Set configuration for loopback traffic Configure the loopback interface to accept traffic. Configure all other interfaces to deny traffic to the loopback network. Loopback traffic is generated between processes on machine and is typically critical to operation of the system. The loopback interface is the only place that loopback network traffic should be seen, all other interfaces should ignore traffic on this network as an anti-spoofing measure.
CCE-94002-3 Set configuration for IPv6 loopback traffic Configure the loopback interface to accept traffic. Configure all other interfaces to deny traffic to the loopback network. Loopback traffic is generated between processes on machine and is typically critical to operation of the system. The loopback interface is the only place that loopback network traffic should be seen, all other interfaces should ignore traffic on this network as an anti-spoofing measure.
CCE-94003-1 Set Default ip6tables Policy for Incoming Packets To set the default policy to DROP (instead of ACCEPT) for the built-in INPUT chain which processes incoming packets, add or correct the following line in /etc/sysconfig/ip6tables:
:INPUT DROP [0:0]
If changes were required, reload the ip6tables rules:
$ sudo service ip6tables reload
In ip6tables, the default policy is applied only after all the applicable rules in the table are examined for a match. Setting the default policy to DROP implements proper design for a firewall, i.e. any packets which are not explicitly permitted should not be accepted.
CCE-94004-9 Verify iptables Enabled The iptables service can be enabled with the following command:
$ sudo systemctl enable iptables.service
The iptables service provides the system's host-based firewalling capability for IPv4 and ICMP.
CCE-94005-6 Ensure iptables are flushed nftables is a replacement for iptables, ip6tables, ebtables and arptables It is possible to mix iptables and nftables. However, this increases complexity and also the chance to introduce errors. For simplicity flush out all iptables rules, and ensure it is not loaded.
CCE-94006-4 Install iptables Package The iptables package can be installed with the following command:
$ sudo zypper install iptables
iptables controls the Linux kernel network packet filtering code. iptables allows system operators to set up firewalls and IP masquerading, etc.
CCE-94007-2 Verify firewalld service disabled Firewalld (Dynamic Firewall Manager) provides a dynamically managed firewall with support for network/firewall “zones” to assign a level of trust to a network and its associated connections, interfaces or sources. It has support for IPv4, IPv6, Ethernet bridges and also for IPSet firewall settings. There is a separation of the runtime and permanent configuration options. The firewalld service can be disabled with the following command:
$ sudo systemctl mask --now firewalld.service
Running Firewalld along other service with the same functionality may lead to conflict and unexpected results.
CCE-94008-0 Uninstall firewalld Package firewalld (Dynamic Firewall Manager) provides a dynamically managed firewall with support for network/firewall “zones” to assign a level of trust to a network and its associated connections, interfaces or sources. It has support for IPv4, IPv6, Ethernet bridges and also for IPSet firewall settings. There is a separation of the runtime and permanent configuration options. The firewalld package can be removed with the following command:
$ sudo zypper remove firewalld
Running both nftables.service and firewalld.service may lead to conflict and unexpected results.
CCE-94009-8 Set Default firewalld Zone for Incoming Packets To set the default zone to drop for the built-in default zone which processes incoming IPv4 and IPv6 packets, modify the following line in /etc/firewalld/firewalld.conf to be:
DefaultZone=drop
In firewalld the default zone is applied only after all the applicable rules in the table are examined for a match. Setting the default zone to drop implements proper design for a firewall, i.e. any packets which are not explicitly permitted should not be accepted.
CCE-94010-6 Install firewalld Package The firewalld package can be installed with the following command:
$ sudo zypper install firewalld
"Firewalld" provides an easy and effective way to block/limit remote access to the system via ports, services, and protocols. Remote access services, such as those providing remote access to network devices and information systems, which lack automated control capabilities, increase risk and make remote user access management difficult at best. Remote access is access to nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. SUSE Linux Enterprise Micro 5 functionality (e.g., SSH) must be capable of taking enforcement action if the audit reveals unauthorized activity. Automated control of remote access sessions allows organizations to ensure ongoing compliance with remote access policies by enforcing connection rules of remote access applications on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets)."
CCE-94011-4 Ensure Unnecessary Services and Ports Are Not Accepted Services and ports can be accepted or explicitly rejected or dropped by a zone. For every zone, a default behavior can be set that handles incoming traffic that is not further specified. Such behavior is defined by setting the target of the zone. The possible options are: - ACCEPT - accepts all incoming packets except those disabled by a specific rule. - REJECT - disables all incoming packets except those that have been allowed in specific rules and the source machine is informed about the rejection. - DROP - disables all incoming packets except those that have been allowed in specific rules and no information sent to the source machine. To reduce the attack surface of a system, all services and ports should be blocked unless required.
CCE-94012-2 Configure Firewalld to Use the Nftables Backend Firewalld can be configured with many backends, such as nftables. Nftables is modern kernel module for controlling network connections coming into a system. Utilizing the limit statement in "nftables" can help to mitigate DoS attacks.
CCE-94013-0 Enable logrotate Timer The logrotate timer can be enabled with the following command:
$ sudo systemctl enable logrotate.timer
Log files that are not properly rotated run the risk of growing so large that they fill up the /var/log partition. Valuable logging information could be lost if the /var/log partition becomes full.
CCE-94014-8 Ensure Logrotate Runs Periodically The logrotate utility allows for the automatic rotation of log files. The frequency of rotation is specified in /etc/logrotate.conf, which triggers a cron task or a timer. To configure logrotate to run daily, add or correct the following line in /etc/logrotate.conf:
# rotate log files frequency
daily
Log files that are not properly rotated run the risk of growing so large that they fill up the /var/log partition. Valuable logging information could be lost if the /var/log partition becomes full.
CCE-94015-5 Ensure logrotate is Installed logrotate is installed by default. The logrotate package can be installed with the following command:
 $ sudo zypper install logrotate
The logrotate package provides the logrotate services.
CCE-94016-3 Ensure journald is configured to write log files to persistent disk The journald system may store log files in volatile memory or locally on disk. If the logs are only stored in volatile memory they will be lost upon reboot. Log files contain valuable data and need to be persistent to aid in possible investigations.
CCE-94017-1 Ensure journald is configured to send logs to rsyslog Data from journald may be stored in volatile memory or persisted locally. Utilities exist to accept remote export of journald logs. Storing log data on a remote host protects log integrity from local attacks. If an attacker gains root access on the local system, they could tamper with or remove log data that is stored on the local system.
CCE-94018-9 Ensure journald is configured to compress large log files The journald system can compress large log files to avoid fill the system disk. Log files that are not properly compressed run the risk of growing so large that they fill up the log partition. Valuable logging information could be lost if the log partition becomes full.
CCE-94019-7 Verify /boot/grub2/grub.cfg Permissions File permissions for /boot/grub2/grub.cfg should be set to 600. To properly set the permissions of /boot/grub2/grub.cfg, run the command:
$ sudo chmod 600 /boot/grub2/grub.cfg
Proper permissions ensure that only the root user can modify important boot parameters.
CCE-94020-5 Verify /boot/grub2/grub.cfg User Ownership The file /boot/grub2/grub.cfg should be owned by the root user to prevent destruction or modification of the file. To properly set the owner of /boot/grub2/grub.cfg, run the command:
$ sudo chown root /boot/grub2/grub.cfg 
Only root should be able to modify important boot parameters.
CCE-94021-3 Verify /boot/grub2/grub.cfg Group Ownership The file /boot/grub2/grub.cfg should be group-owned by the root group to prevent destruction or modification of the file. To properly set the group owner of /boot/grub2/grub.cfg, run the command:
$ sudo chgrp root /boot/grub2/grub.cfg
The root group is a highly-privileged group. Furthermore, the group-owner of this file should not have any access privileges anyway.
CCE-94022-1 Install the pam_apparmor Package The pam_apparmor package can be installed with the following command:
$ sudo zypper install pam_apparmor
Protection of system integrity using AppArmor depends on this package being installed.
CCE-94023-9 Ensure the Default Bash Umask is Set Correctly To ensure the default umask for users of the Bash shell is set properly, add or correct the umask setting in /etc/bash.bashrc to read as follows:
umask 027
The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read or written to by unauthorized users.
CCE-94024-7 Ensure the Default Umask is Set Correctly in /etc/profile To ensure the default umask controlled by /etc/profile is set properly, add or correct the umask setting in /etc/profile to read as follows:
umask 027
Note that /etc/profile also reads scripts within /etc/profile.d directory. These scripts are also valid files to set umask value. Therefore, they should also be considered during the check and properly remediated, if necessary.
The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read or written to by unauthorized users.
CCE-94025-4 Ensure that Root's Path Does Not Include Relative Paths or Null Directories Ensure that none of the directories in root's path is equal to a single . character, or that it contains any instances that lead to relative path traversal, such as .. or beginning a path without the slash (/) character. Also ensure that there are no "empty" elements in the path, such as in these examples:
PATH=:/bin
PATH=/bin:
PATH=/bin::/sbin
These empty elements have the same effect as a single . character.
Including these entries increases the risk that root could execute code from an untrusted location.
CCE-94026-2 Ensure that Root's Path Does Not Include World or Group-Writable Directories For each element in root's path, run:
# ls -ld DIR
and ensure that write permissions are disabled for group and other.
Such entries increase the risk that root could execute code provided by unprivileged users, and potentially malicious code.
CCE-94027-0 Ensure users' .netrc Files are not group or world accessible While the system administrator can establish secure permissions for users' .netrc files, the users can easily override these. This rule ensures every .netrc file or directory under the home directory related to an interactive user is not group or world accessible .netrc files may contain unencrypted passwords that may be used to attack other systems. Note: While the complete removal of .netrc files is recommended, if any are required on the system, secure permissions must be applied.
CCE-94028-8 All User Files and Directories In The Home Directory Must Have Mode 0750 Or Less Permissive Set the mode on files and directories in the local interactive user home directory with the following command:
$ sudo chmod 0750 /home/USER/FILE_DIR
Files that begin with a "." are excluded from this requirement.
If a local interactive user files have excessive permissions, unintended users may be able to access or modify them.
CCE-94029-6 Enforce Usage of pam_wheel with Group Parameter for su Authentication To ensure that only users who are members of the group set in the group option of pam_wheel.so module can run commands with altered privileges through the su command, make sure that the following line exists in the file /etc/pam.d/su:
auth required pam_wheel.so use_uid group=sugroup
The su program allows to run commands with a substitute user and group ID. It is commonly used to run commands as the root user. Limiting access to such command is considered a good security practice.
CCE-94030-4 Restrict Virtual Console Root Logins To restrict root logins through the (deprecated) virtual console devices, ensure lines of this form do not appear in /etc/securetty:
vc/1
vc/2
vc/3
vc/4
Preventing direct root login to virtual console devices helps ensure accountability for actions taken on the system using the root account.
CCE-94031-2 Direct root Logins Not Allowed To further limit access to the root account, administrators can disable root logins at the console by editing the /etc/securetty file. This file lists all devices the root user is allowed to login to. If the file does not exist at all, the root user can login through any communication device on the system, whether via the console or via a raw network interface. This is dangerous as user can login to the system as root via Telnet, which sends the password in plain text over the network. By default, SUSE Linux Enterprise Micro 5's /etc/securetty file only allows the root user to login at the console physically attached to the system. To prevent root from logging in, remove the contents of this file. To prevent direct root logins, remove the contents of this file by typing the following command:
$ sudo echo > /etc/securetty
Disabling direct root logins ensures proper accountability and multifactor authentication to privileged accounts. Users will first login, then escalate to privileged (root) access via su / sudo. This is required for FISMA Low and FISMA Moderate systems.
CCE-94032-0 Ensure the Group Used by pam_wheel.so Module Exists on System and is Empty Ensure that the group sugroup referenced by var_pam_wheel_group_for_su variable and used as value for the pam_wheel.so group option exists and has no members. This empty group used by pam_wheel.so in /etc/pam.d/su ensures that no user can run commands with altered privileges through the su command. The su program allows to run commands with a substitute user and group ID. It is commonly used to run commands as the root user. Limiting access to such command is considered a good security practice.
CCE-94033-8 Verify Root Has A Primary GID 0 The root user should have a primary group of 0. To help ensure that root-owned files are not inadvertently exposed to other users.
CCE-94034-6 Verify No netrc Files Exist The .netrc files contain login information used to auto-login into FTP servers and reside in the user's home directory. These files may contain unencrypted passwords to remote FTP servers making them susceptible to access by unauthorized users and should not be used. Any .netrc files should be removed. Unencrypted passwords for remote FTP servers may be stored in .netrc files.
CCE-94035-3 Ensure there are no legacy + NIS entries in /etc/shadow The + character in /etc/shadow file marks a place where entries from a network information service (NIS) should be directly inserted. Using this method to include entries into /etc/shadow is considered legacy and should be avoided. These entries may provide a way for an attacker to gain access to the system.
CCE-94036-1 Ensure there are no legacy + NIS entries in /etc/passwd The + character in /etc/passwd file marks a place where entries from a network information service (NIS) should be directly inserted. Using this method to include entries into /etc/passwd is considered legacy and should be avoided. These entries may provide a way for an attacker to gain access to the system.
CCE-94037-9 Verify No .forward Files Exist The .forward file specifies an email address to forward the user's mail to. Use of the .forward file poses a security risk in that sensitive data may be inadvertently transferred outside the organization. The .forward file also poses a risk as it can be used to execute commands that may perform unintended actions.
CCE-94038-7 All GIDs referenced in /etc/passwd must be defined in /etc/group Add a group to the system for each GID referenced without a corresponding group. If a user is assigned the Group Identifier (GID) of a group not existing on the system, and a group with the Group Identifier (GID) is subsequently created, the user may have unintended rights to any files associated with the group.
CCE-94039-5 Ensure all users last password change date is in the past All users should have a password change date in the past. If a user recorded password change date is in the future then they could bypass any set password expiration.
CCE-94040-3 Verify All Account Password Hashes are Shadowed If any password hashes are stored in /etc/passwd (in the second field, instead of an x or *), the cause of this misconfiguration should be investigated. The account should have its password reset and the hash should be properly stored, or the account should be deleted entirely. The hashes for all user account passwords should be stored in the file /etc/shadow and never in /etc/passwd, which is readable by all users.
CCE-94041-1 Set existing passwords a period of inactivity before they been locked Configure user accounts that have been inactive for over a given period of time to be automatically disabled by running the following command:
$ sudo chage --inactive 30 USER
Inactive accounts pose a threat to system security since the users are not logging in to notice failed login attempts or other anomalies.
CCE-94042-9 Set Password Warning Age To specify how many days prior to password expiration that a warning will be issued to users, edit the file /etc/login.defs and add or correct the following line:
PASS_WARN_AGE 7
The profile requirement is 7.
Setting the password warning age enables users to make the change at a practical time.
CCE-94043-7 Set Existing Passwords Warning Age To configure how many days prior to password expiration that a warning will be issued to users, run the command:
$ sudo chage --warndays 7 USER
This profile requirement is 7.
Providing an advance warning that a password will be expiring gives users time to think of a secure password. Users caught unaware may choose a simple password or write it down where it may be discovered.
CCE-94044-5 Ensure shadow Group is Empty The shadow group allows system programs which require access the ability to read the /etc/shadow file. No users should be assigned to the shadow group. Any users assigned to the shadow group would be granted read access to the /etc/shadow file. If attackers can gain read access to the /etc/shadow file, they can easily run a password cracking program against the hashed passwords to break them. Other security information that is stored in the /etc/shadow file (such as expiration) could also be useful to subvert additional user accounts.
CCE-94045-2 Ensure All Accounts on the System Have Unique Names Ensure accounts on the system have unique names. To ensure all accounts have unique names, run the following command:
$ sudo getent passwd | awk -F: '{ print $1}' | uniq -d
If a username is returned, change or delete the username.
Unique usernames allow for accountability on the system.
CCE-94046-0 Ensure All Groups on the System Have Unique Group Names Change the group name or delete groups, so each has a unique name. To assure accountability and prevent unauthenticated access, groups must be identified uniquely to prevent potential misuse and compromise of the system.
CCE-94047-8 Ensure All Groups on the System Have Unique Group ID Change the group name or delete groups, so each has a unique id. To assure accountability and prevent unauthenticated access, groups must be identified uniquely to prevent potential misuse and compromise of the system.
CCE-94048-6 Require Authentication for Single User Mode Single-user mode is intended as a system recovery method, providing a single user root access to the system by providing a boot option at startup.

By default, single-user mode is protected by requiring a password and is set in /usr/lib/systemd/system/rescue.service.
This prevents attackers with physical access from trivially bypassing security on the machine and gaining root access. Such accesses are further prevented by configuring the bootloader password.
CCE-94049-4 Require Authentication for Emergency Systemd Target Emergency mode is intended as a system recovery method, providing a single user root access to the system during a failed boot sequence.

By default, Emergency mode is protected by requiring a password and is set in /usr/lib/systemd/system/emergency.service.
This prevents attackers with physical access from trivially bypassing security on the machine and gaining root access. Such accesses are further prevented by configuring the bootloader password.
CCE-94050-2 Set Lockout Time for Failed Password Attempts using pam_tally2 This rule configures the system to lock out accounts during a specified time period after a number of incorrect login attempts using pam_tally2.so. By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking the account.
CCE-94051-0 Configure the root Account lock for Failed Password Attempts via pam_tally2 This rule configures the system to lock out the root account after a number of incorrect login attempts using pam_tally2.so. By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking the account.
CCE-94052-8 Verify permissions on Message of the Day Banner To properly set the permissions of /etc/motd, run the command:
$ sudo chmod 0644 /etc/motd
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
Proper permissions will ensure that only root user can modify the banner.
CCE-94053-6 Verify permissions on System Login Banner for Remote Connections To properly set the permissions of /etc/issue.net, run the command:
$ sudo chmod 0644 /etc/issue.net
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
Proper permissions will ensure that only root user can modify the banner.
CCE-94054-4 Verify permissions on System Login Banner To properly set the permissions of /etc/issue, run the command:
$ sudo chmod 0644 /etc/issue
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
Proper permissions will ensure that only root user can modify the banner.
CCE-94055-1 Verify ownership of Message of the Day Banner To properly set the owner of /etc/motd, run the command:
$ sudo chown root /etc/motd 
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
Proper ownership will ensure that only root user can modify the banner.
CCE-94056-9 Verify ownership of System Login Banner for Remote Connections To properly set the owner of /etc/issue.net, run the command:
$ sudo chown root /etc/issue.net 
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
Proper ownership will ensure that only root user can modify the banner.
CCE-94057-7 Verify ownership of System Login Banner To properly set the owner of /etc/issue, run the command:
$ sudo chown root /etc/issue 
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
Proper ownership will ensure that only root user can modify the banner.
CCE-94058-5 Verify Group Ownership of Message of the Day Banner To properly set the group owner of /etc/motd, run the command:
$ sudo chgrp root /etc/motd
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
Proper group ownership will ensure that only root user can modify the banner.
CCE-94059-3 Verify Group Ownership of System Login Banner for Remote Connections To properly set the group owner of /etc/issue.net, run the command:
$ sudo chgrp root /etc/issue.net
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
Proper group ownership will ensure that only root user can modify the banner.
CCE-94060-1 Verify Group Ownership of System Login Banner To properly set the group owner of /etc/issue, run the command:
$ sudo chgrp root /etc/issue
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
Proper group ownership will ensure that only root user can modify the banner.
CCE-94061-9 Modify the System Message of the Day Banner To configure the system message banner edit /etc/motd. Replace the default text with a message compliant with the local site policy or a legal disclaimer. The DoD required text is either:

You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access controls) to protect USG interests -- not for your personal benefit or privacy.
-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.


OR:

I've read & consent to terms in IS user agreem't.
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.

System use notifications are required only for access via login interfaces with human users and are not required when such human interfaces do not exist.
CCE-94062-7 Modify the System Login Banner for Remote Connections To configure the system login banner edit /etc/issue.net. Replace the default text with a message compliant with the local site policy or a legal disclaimer. The DoD required text is either:

You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access controls) to protect USG interests -- not for your personal benefit or privacy.
-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.


OR:

I've read & consent to terms in IS user agreem't.
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.

System use notifications are required only for access via login interfaces with human users and are not required when such human interfaces do not exist.
CCE-94063-5 Ensure package manager repositories are configured Systems need to have package manager repositories configured to ensure they receive the latest patches and updates. If the system's package repositories are misconfigured important patches may not be identified or a rogue repository could introduce compromised software.
CCE-94064-3 Verify the system-wide library files in directories "/lib", "/lib64", "/usr/lib/" and "/usr/lib64" are group-owned by root. System-wide library files are stored in the following directories by default:
/lib
/lib64
/usr/lib
/usr/lib64
All system-wide shared library files should be protected from unauthorised access. If any of these files is not group-owned by root, correct its group-owner with the following command:
$ sudo chgrp root FILE
If the operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
CCE-94065-0 Verify that Shared Library Files Have Restrictive Permissions System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are stored in /lib/modules. All files in these directories should not be group-writable or world-writable. If any file in these directories is found to be group-writable or world-writable, correct its permission with the following command:
$ sudo chmod go-w FILE
Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Restrictive permissions are necessary to protect the integrity of the system.
CCE-94066-8 Verify that Shared Library Files Have Root Ownership System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are also stored in /lib/modules. All files in these directories should be owned by the root user. If the directory, or any file in these directories, is found to be owned by a user other than root correct its ownership with the following command:
$ sudo chown root FILE
Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Proper ownership is necessary to protect the integrity of the system.
CCE-94067-6 Verify that Shared Library Directories Have Restrictive Permissions System-wide shared library directories, which contain are linked to executables during process load time or run time, are stored in the following directories by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are stored in /lib/modules. All sub-directories in these directories should not be group-writable or world-writable. If any file in these directories is found to be group-writable or world-writable, correct its permission with the following command:
$ sudo chmod go-w DIR
If the operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
CCE-94068-4 Verify that Shared Library Directories Have Root Ownership System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are also stored in /lib/modules. All files in these directories should be owned by the root user. If the directories, is found to be owned by a user other than root correct its ownership with the following command:
$ sudo chown root DIR
Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Proper ownership of library directories is necessary to protect the integrity of the system.
CCE-94069-2 Verify that Shared Library Directories Have Root Group Ownership System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are also stored in /lib/modules. All files in these directories should be group-owned by the root user. If the directories, is found to be owned by a user other than root correct its ownership with the following command:
$ sudo chgrp root DIR
Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Proper ownership of library directories is necessary to protect the integrity of the system.
CCE-94070-0 Ensure gpgcheck Enabled for All zypper Package Repositories To ensure signature checking is not disabled for any repos, remove any lines from files in /etc/zypp/repos.d of the form:
gpgcheck=0
Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This ensures the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. Certificates used to verify the software must be from an approved Certificate Authority (CA)."
CCE-94071-8 Ensure auditd Collects Information on the Use of Privileged Commands - ssh-keysign At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/lib/ssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/lib/ssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-94072-6 Ensure GPG keys are configured The operation system or installed application can be successfully bootstrapped without the GPG key being trusted. However, you cannot install new packages or update them until the keys are trusted.

Most packages managers implement GPG key signing to verify package integrity during installation.

To verify GPG keys are configured correctly for your package manager, one of the following command groups may provide the needed information depending on the package manager in use.

In SUSE Linux distributions, the administrators have to follow the next steps:
1. Log on to the system as a user with administrator rights.
2. Locate and download package, for example zoom_x86_64.rpm
3. Locate and download the public key (GPG) from the software download site, for example the key for zoom package is package-signing-key-5-12-6.pub
4. Import the key public key:
$ sudo rpm --import package-signing-key-5-12-6.pub
5. List the keys, for example the command:
$ sudo rpm -qa gpg-pubkey*
will provide:
gpg-pubkey-dd79b481-62fe7502
6. Get more details about the key, via the command:
$ sudo rpm -qa gpg-pubkey-dd79b481-62fe7502
7. Check the GPG key, for example the command:
$ sudo rpm -q gpg-pubkey --qf '%{name}-%{version}-%{release} --> %{summary}\n'
will provide:
gpg-pubkey-dd79b481-62fe7502 --> gpg(Zoom Video Communications, Inc. <CryptoOpsCodeSignProd@zoom.us>)


It is important to ensure that updates are obtained from a valid source to protect against spoofing that could lead to the inadvertent installation of malware on the system.
CCE-94073-4 Ensure Sudo Logfile Exists - sudo logfile A custom log sudo file can be configured with the 'logfile' tag. This rule configures a sudo custom logfile at the default location suggested by CIS, which uses /var/log/sudo.log. A sudo log file simplifies auditing of sudo commands.
CCE-94074-2 Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo use_pty The sudo use_pty tag, when specified, will only execute sudo commands from users logged in to a real tty. This should be enabled by making sure that the use_pty tag exists in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/. Requiring that sudo commands be run in a pseudo-terminal can prevent an attacker from retaining access to the user's terminal after the main program has finished executing.
CCE-94075-9 Install sudo Package The sudo package can be installed with the following command:
$ sudo zypper install sudo
sudo is a program designed to allow a system administrator to give limited root privileges to users and log root activity. The basic philosophy is to give as few privileges as possible but still allow system users to get their work done.
CCE-94076-7 Ensure /dev/shm is configured The /dev/shm is a traditional shared memory concept. One program will create a memory portion, which other processes (if permitted) can access. If /dev/shm is not configured, tmpfs will be mounted to /dev/shm by systemd. Any user can upload and execute files inside the /dev/shm similar to the /tmp partition. Configuring /dev/shm allows an administrator to set the noexec option on the mount, making /dev/shm useless for an attacker to install executable code. It would also prevent an attacker from establishing a hardlink to a system setuid program and wait for it to be updated. Once the program was updated, the hardlink would be broken and the attacker would have his own copy of the program. If the program happened to have a security vulnerability, the attacker could continue to exploit the known flaw.
CCE-94077-5 Ensure rsyncd service is disabled The rsyncd service can be disabled with the following command:
$ sudo systemctl mask --now rsyncd.service
The rsyncd service presents a security risk as it uses unencrypted protocols for communication.
CCE-94078-3 Disable Prelinking The prelinking feature changes binaries in an attempt to decrease their startup time. In order to disable it, change or add the following line inside the file /etc/sysconfig/prelink:
PRELINKING=no
Next, run the following command to return binaries to a normal, non-prelinked state:
$ sudo /usr/sbin/prelink -ua
Because the prelinking feature changes binaries, it can interfere with the operation of certain software and/or modes such as AIDE, FIPS, etc.
CCE-94079-1 Add noexec Option to /tmp The noexec mount option can be used to prevent binaries from being executed out of /tmp. Add the noexec option to the fourth column of /etc/fstab for the line which controls mounting of /tmp. Allowing users to execute binaries from world-writable directories such as /tmp should never be necessary in normal operation and can expose the system to potential compromise.
CCE-94080-9 Configure systemd-journal-upload TLS parameters: ServerKeyFile, ServerCertificateFile and TrustedCertificateFile SUSE Linux Enterprise Micro 5 must offload rsyslog messages for networked systems in real time and offload standalone systems at least weekly Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Offloading is a common process in information systems with limited audit storage capacity
CCE-94081-7 Configure systemd-journal-upload URL SUSE Linux Enterprise Micro 5 must offload rsyslog messages for networked systems in real time and offload standalone systems at least weekly Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Offloading is a common process in information systems with limited audit storage capacity
CCE-94082-5 Limit Password Reuse Do not allow users to reuse recent passwords. This can be accomplished by using the remember option for the pam_pwhistory PAM modules.

In the file /etc/pam.d/common-password, make sure the parameters remember and use_authtok are present, and that the value for the remember parameter is 5 or greater. For example:
password requisite pam_pwhistory.so ...existing_options... remember=5 use_authtok
The profile requirement is 5 passwords.
Preventing reuse of previous passwords helps ensure that a compromised password is not reused by a user.
CCE-94084-1 Enable systemd-journal-upload Service The systemd-journal-upload service is part of the systemd-journal-remote package and enables centralized logging by uploading local systemd journal entries to a remote log server via HTTPS. This service acts as a client that pushes journal data to a remote host running the systemd-journal-remote receiver service. The systemd-journal-upload service can be enabled with the following command:
$ sudo systemctl enable systemd-journal-upload.service
Centralized logging through systemd-journal-upload is essential for security monitoring, incident response, and compliance requirements. Storing log data on a remote host protects log integrity from local attacks. If an attacker gains root access on the local system, they could tamper with or remove log data stored locally to hide their activities. Remote logging ensures that audit trails remain intact even if the local system is compromised. Additionally, centralized logs facilitate correlation of events across multiple systems, enabling better detection of distributed attacks and security incidents.
CCE-94085-8 Install systemd-journal-remote Package Journald (via systemd-journal-remote ) supports the ability to send log events it gathers to a remote log host or to receive messages from remote hosts, thus enabling centralised log management. Storing log data on a remote host protects log integrity from local attacks. If an attacker gains root access on the local system, they could tamper with or remove log data that is stored on the local system.
CCE-94086-6 OpenSSH Service Must Use Passcode for Their Private Keys Verify the SSH private key files have a passcode. For each private key stored on the system, use the following command:
$ sudo ssh-keygen -y -f /path/to/file
If the contents of the key are displayed, without asking a passphrase this is a finding.
If an unauthorized user obtains access to a private key without a passcode, that user would have unauthorized access to any system where the associated public key has been installed.
CCE-94087-4 Map System Users To The Appropriate SELinux Role Configure the operating system to prevent non-privileged users from executing privileged functions to include disabling, circumventing, or altering implemented security safeguards/countermeasures. All administrators must be mapped to the sysadm_u or staff_u users with the appropriate domains (sysadm_t and staff_t).
$ sudo semanage login -m -s sysadm_u USER
or
$ sudo semanage login -m -s staff_u USER


All authorized non-administrative users must be mapped to the user_u role or the appropriate domain (user_t).
$ sudo semanage login -m -s user_u USER
Preventing non-privileged users from executing privileged functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges.

Privileged functions include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals who do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users.
CCE-94088-2 An SELinux Context must be configured for default pam_tally2 file option The file configuration option in PAM pam_tally2.so module defines where to keep counts. Default is /var/log/tallylog. The configured directory must have the correct SELinux context. Not having the correct SELinux context on the pam_tally2.so file may lead to unauthorized access to the directory.
CCE-94089-0 SLEM 5 must use the default pam_tally2 tally directory. This rule configures the system to use default pam_tally2 tally directory By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account.
CCE-94090-8 Configure a Sufficiently Large Partition for Audit Logs The SUSE Linux Enterprise Micro 5 operating system must allocate audit record storage capacity to store at least one weeks worth of audit records when audit records are not immediately sent to a central audit record storage facility. The partition size needed to capture a week's worth of audit records is based on the activity level of the system and the total storage capacity available. In normal circumstances, 10.0 GB of storage space for audit records will be sufficient. Determine which partition the audit records are being written to with the following command:
$ sudo grep log_file /etc/audit/auditd.conf
log_file = /var/log/audit/audit.log
Check the size of the partition that audit records are written to with the following command:
$ sudo df -h /var/log/audit/
/dev/sda2 24G 10.4G 13.6G 43% /var/log/audit
Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity.
CCE-94091-6 Install policycoreutils-python-utils package The policycoreutils-python-utils package can be installed with the following command:
$ sudo zypper install policycoreutils-python-utils
This package is required to operate and manage an SELinux environment and its policies. It provides utilities such as semanage, audit2allow, audit2why, chcat and sandbox.
CCE-94092-4 Enforce Delay After Failed Logon Attempts To configure the system to introduce a delay after failed logon attempts, add or correct the pam_faildelay settings in /etc/pam.d/common-auth to make sure its delay parameter is at least 4000000 or greater. For example:
auth required pam_faildelay.so delay=4000000
Limiting the number of logon attempts over a certain time interval reduces the chances that an unauthorized user may gain access to an account.
CCE-94093-2 Ensure the Logon Failure Delay is Set Correctly in login.defs To ensure the logon failure delay controlled by /etc/login.defs is set properly, add or correct the FAIL_DELAY setting in /etc/login.defs to read as follows:
FAIL_DELAY 4
Increasing the time between a failed authentication attempt and re-prompting to enter credentials helps to slow a single-threaded brute force attack.
CCE-94094-0 Ensure SELinux State is Enforcing The SELinux state should be set to enforcing at system boot time. In the file /etc/selinux/config, add or correct the following line to configure the system to boot into enforcing mode:
SELINUX=enforcing
Ensure that all files have correct SELinux labels by running:
fixfiles onboot
Then reboot the system.
Setting the SELinux state to enforcing ensures SELinux is able to confine potentially compromised processes to the security policy, which is designed to prevent them from causing damage to the system or further elevating their privileges.
CCE-94095-7 Configure SELinux Policy The SELinux targeted policy is appropriate for general-purpose desktops and servers, as well as systems in many other roles. To configure the system to use this policy, add or correct the following line in /etc/selinux/config:
SELINUXTYPE=targeted
Other policies, such as mls, provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.
Setting the SELinux policy to targeted or a more specialized policy ensures the system will confine processes that are likely to be targeted for exploitation, such as network or system services.

Note: During the development or debugging of SELinux modules, it is common to temporarily place non-production systems in permissive mode. In such temporary cases, SELinux policies should be developed, and once work is completed, the system should be reconfigured to .
CCE-94096-5 Ensure the default plugins for the audit dispatcher are Installed The audit-audispd-plugins package should be installed. Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity.
CCE-94097-3 Install policycoreutils Package The policycoreutils package can be installed with the following command:
$ sudo zypper install policycoreutils
Security-enhanced Linux is a feature of the Linux kernel and a number of utilities with enhanced security functionality designed to add mandatory access controls to Linux. The Security-enhanced Linux kernel contains new architectural components originally developed to improve security of the Flask operating system. These architectural components provide general support for the enforcement of many kinds of mandatory access control policies, including those based on the concepts of Type Enforcement, Role-based Access Control, and Multi-level Security. policycoreutils contains the policy core utilities that are required for basic operation of an SELinux-enabled system. These utilities include load_policy to load SELinux policies, setfiles to label filesystems, newrole to switch roles, and so on.
CCE-94098-1 Record Any Attempts to Run semanage At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-94099-9 Record Any Attempts to Run setfiles At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
CCE-94100-5 Record Any Attempts to Run setsebool At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.