Group
Guide to the Secure Configuration of Firefox
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Group
Firefox
Group contains 1 group and 34 rules |
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Firefox is an open-source web browser and developed by Mozilla.
Web browsers such as Firefox are used for a number of reasons. This section
provides settings for configuring Firefox policies to meet compliance
settings for Firefox running on Red Hat Enterprise Linux systems.
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Group
The DoD Root Certificate Is Required
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The Shared System Certificates store contains certificates that
applications can access for a single certificate repository.
If enabled, Firefox can access that single system certificate
repository. If the DoD root certificate is also installed into
the shared system certificate repository, Firefox will see and
use the DoD root certificate as a valid certificate authority. |
Rule
The DoD Root Certificate Exists
[ref] | The DoD root certificate should be installed in the Shared System Certificates store
for Firefox to be able to access the DoD certificate. To install the root certificated
into the Shared System Certificates store, copy the DoD root certificate into
/etc/pki/ca-trust/source/anchors . Once the file is copied, run the following
command:
$ sudo update-ca-trust extract
| Rationale: | The DOD root certificate will ensure that the trust chain is
established for server certificates issued from the DOD CA. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_preferences-dod_root_certificate_installed | Identifiers: | CCE-82056-3 | References: | | |
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Rule
Firefox must be configured to disable the installation of extensions.
[ref] | Addon installation may be disabled in an administrative policy by setting
the InstallAddonsPermission key under policies to false . | Rationale: | A browser extension is a program that has been installed into the browser to add functionality. Where a plug-in interacts only with a web page and usually a third-party external application (e.g., Flash, Adobe Reader), an extension interacts with the browser program itself. Extensions are not embedded in web pages and must be downloaded and installed in order to work. Extensions allow browsers to avoid restrictions that apply to web pages.
For example, an extension can be written to combine data from multiple domains and present it when a certain page is accessed, which can be considered cross-site scripting. If a browser is configured to allow unrestricted use of extensions, plug-ins can be loaded and installed from malicious sources and used on the browser. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-addons_permission | References: | | |
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Rule
Firefox autoplay must be disabled.
[ref] | Audio/Video autoplay may be disabled in an administrative policy by setting
the Default key under Permissions , Autoplay to "block-audio-video" . | Rationale: | Autoplay allows the user to control whether videos can play automatically (without user consent) with audio content. The user must be able to select content that is run within the browser window. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-autoplay_video | References: | | |
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Rule
Enabled Firefox Cryptomining protection
[ref] | Cryptomining protection may be enabled by setting
privacy.trackingprotection.cryptomining.enabled to true . | Rationale: | The Content Blocking/Tracking Protection feature stops Firefox from loading content from malicious sites. The content might be a script or an image, for example. If a site is on one of the tracker lists you set Firefox to use, then the fingerprinting script (or other tracking script/image) will not be loaded from that site.
Cryptomining scripts use your computer’s central processing unit (CPU) to invisibly mine cryptocurrency. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-cryptomining | References: | | |
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Rule
Disable Firefox Development Tools
[ref] | Firefox provides development tools which identify detailed information
about the browser and its configuration. These details are often also
recorded into a log file, giving an attacker the ability to capture
detailed information about the system.
This can be disabled by setting DisableDeveloperTools to
true in policies.json
| Rationale: | In order to protect privacy and sensitive data, Mozilla provides
the ability to configure Firefox so that development tools are prevented from being used. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-development_tools | References: | | |
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Rule
Disable Firefox deprecated ciphers
[ref] | Pocket may be disabled by setting
TLS_RSA_WITH_3DES_EDE_CBC_SHA to true under DisabledCiphers
in the policies file. | Rationale: | Weak ciphers are encryption/decryption algorithms that use keys of insufficient length. Using an insufficient length for a key increases
the probability that the encryption scheme could be broken. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-disable_deprecated_ciphers | References: | | |
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Rule
Firefox must be configured to disable form fill assistance.
[ref] | The update check may be disabled in an administrative policy by setting
the DisableFormHistory key under policies to true . | Rationale: | To protect privacy and sensitive data, Firefox provides the ability to configure the program so that data entered into forms is not saved. This mitigates the risk of a website gleaning private information from prefilled information. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-disable_form_history | References: | | |
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Rule
Disable Firefox Pocket
[ref] | Pocket may be disabled by setting
DisablePocket to true
in the policies file. | Rationale: | Pocket is a social bookmarking service for storing, sharing, and discovering web bookmarks.
Data gathering cloud services such as Pocket are generally disabled in the DoD. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-disable_pocket | References: | | |
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Rule
Disable Firefox Studies
[ref] | Pocket may be disabled by setting
DisableFirefoxStudies to true
in the policies file. | Rationale: | Studies try out different features and ideas prior to release to all Firefox users. Testing beta software is not in the DoD user's mission. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-disable_studies | References: | | |
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Rule
Firefox must be configured so that DNS over HTTPS is disabled.
[ref] | DNS over HTTPS feature may be disabled via administrative policy by setting
Enabled under DNSOverHTTPS to false . | Rationale: | DNS over HTTPS has generally not been adopted in the DoD. DNS is tightly controlled.
It is detrimental for applications to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors.
Applications are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions).
Examples of non-essential capabilities include but are not limited to advertising software or browser plug-ins that are not related to requirements or provide a wide array of functionality not required for every mission but that cannot be disabled. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-dns_over_https | References: | | |
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Rule
Firefox encrypted media extensions must be disabled.
[ref] | Firefox's Encrypted Media Extensions support playback of media content that is subject to Digital Right Management.
These extensions may be disabled completely by setting
Enabled under EncryptedMediaExtensions to false
Locked under EncryptedMediaExtensions to true
. | Rationale: | Enable or disable Encrypted Media Extensions and optionally lock it.
If "Enabled" is set to "false", Firefox does not download encrypted media extensions (such as Widevine) unless the user consents to installing them.
If "Locked" is set to "true" and "Enabled" is set to "false", Firefox will not download encrypted media extensions (such as Widevine) or ask the user to install them.
It is detrimental for applications to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors.
Applications are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions).
Examples of non-essential capabilities include but are not limited to advertising software or browser plug-ins that are not related to requirements or provide a wide array of functionality not required for every mission but that cannot be disabled. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-encrypted_media_extensions | References: | | |
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Rule
Enabled Firefox Enhanced Tracking Protection
[ref] | Enhanced Tracking Protection may be enabled by setting
browser.contentblocking.category to strict . | Rationale: | Tracking generally refers to content, cookies, or scripts that can collect your browsing data across multiple sites. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-enhanced_tracking | References: | | |
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Rule
Disabled Firefox Extension Recommendations
[ref] | Extension recommendations may be disabled by setting
extensions.htmlaboutaddons.recommendations.enabled to false in the policy file. | Rationale: | The Recommended Extensions program will make it easier for users to discover extensions that have been reviewed for security, functionality, and user experience. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-extension_recommendation | References: | | |
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Rule
Firefox must be configured to not automatically update installed add-ons and plugins.
[ref] | Firefox has a feature to permit installed add-ons and plugins to automatically update. The check may be disabled in an
administrative policy by setting the ExtensionUpdate key under policies to false . | Rationale: | Automatic updates from untrusted sites puts the entire enclave at risk and may override existing security settings. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-extension_update | References: | | |
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Rule
Firefox feedback reporting must be disabled.
[ref] | Feedback reporting feature may be disabled via administrative policy by setting
DisableFeedbackCommands under policies to true . | Rationale: | Disable the menus for reporting sites (Submit Feedback, Report Deceptive Site).
It is detrimental for applications to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors.
Applications are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions).
Examples of non-essential capabilities include but are not limited to advertising software or browser plug-ins that are not related to requirements or provide a wide array of functionality not required for every mission but that cannot be disabled. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-feedback_reporting | References: | | |
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Rule
Enabled Firefox Fingerprinting Protection
[ref] | Fingerprinting protection may be enabled by setting
Fingerprinting to true under EnableTrackingProtection
in the policies file. | Rationale: | The Content Blocking/Tracking Protection feature stops Firefox from loading content from malicious sites. The content might be a script or an image, for example. If a site is on one of the tracker lists you set Firefox to use, then the fingerprinting script (or other tracking script/image) will not be loaded from that site.
Fingerprinting scripts collect information about your browser and device configuration, such as your operating system, screen resolution, and other settings. By compiling these pieces of data, fingerprinters create a unique profile of you that can be used to track you around the Web. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-fingerprinting_protection | References: | | |
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Rule
Firefox must prevent the user from quickly deleting data.
[ref] | The update check may be disabled in an administrative policy by setting
the DisableForgetButton key under policies to true . | Rationale: | There should not be an option for a user to "forget" work they have done. This is required to meet non-repudiation controls. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-forget_button | References: | | |
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Rule
Disable JavaScript's Raise Or Lower Windows Capability
[ref] | JavaScript can configure and make changes to the web browser's appearance by
specifically raising and lowering windows. This can be disabled by
setting dom.disable_window_flip to true in the policy file. | Rationale: | JavaScript can make changes to the browser’s appearance. Allowing a website
to use JavaScript to raise and lower browser windows may disguise an attack. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-javascript_window_changes | References: | | |
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Rule
Disable JavaScript's Moving Or Resizing Windows Capability
[ref] | JavaScript can configure and make changes to the web browser's appearance by
specifically moving and resizing browser windows. This can be disabled by
setting dom.disable_window_move_resize to true in the policy file. | Rationale: | JavaScript can make changes to the browser’s appearance. This activity
can help disguise an attack taking place in a minimized background window. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-javascript_window_resizing | References: | | |
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Rule
Disable Firefox network prediction
[ref] | Firefox has a feature where it predicts and caches DNS requests.
This can be disabled by
setting NetworkPrediction to true in the policy file. | Rationale: | With network prediction enabled, URL requests are made without user consent.
Browsers should always make a direct DNS request with prefetching. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-network_prediction | References: | | |
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Rule
Firefox must be configured to not delete data upon shutdown.
[ref] | The default certificate to present may be configured by setting multiple options
under SanitizeOnShutdown key.
| Rationale: | For diagnostic purposes, data must remain behind when the browser is closed. This is required to meet non-repudiation controls. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-no_sanitize_on_shutdown | References: | | |
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Rule
The Firefox New Tab page must not show Top Sites, Sponsored Top sites, Pocket Recommendations, Sponsored Pocket Stories, Searches, Highlights, or Snippets.
[ref] | Display of top sites may be disabled in an administrative policy by setting the following items under FirefoxHome
to false and by setting the locked key to true .
Search
TopSites
SponsoredTopSites
Pocket
SponsoredPocket
Highlights
Snippets
| Rationale: | The New Tab page by default shows a list of built-in top sites, as well as the top sites the user has visited.
It is detrimental for applications to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors.
Applications are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions).
Examples of non-essential capabilities include but are not limited to advertising software or browser plug-ins that are not related to requirements or provide a wide array of functionality not required for every mission but that cannot be disabled.
The new tab page must not actively show user activity. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-nonessential_capabilities | References: | | |
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Rule
Firefox must be configured to not use a password store with or without a master password.
[ref] | The update check may be disabled in an administrative policy by setting
the PasswordManager key under policies to false . | Rationale: | Firefox can be set to store passwords for sites visited by the user. These individual passwords are stored in a file and can be protected by a master password. Autofill of the password can then be enabled when the site is visited. This feature could also be used to autofill the certificate PIN, which could lead to compromise of DoD information. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-password_manager | References: | | |
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Rule
Enable Firefox Pop-up Blocker
[ref] | The pop-up blocker can be enabled by setting
Default key under PopupBlocking to true in policies.json .
Allowed may be set to a list of sites allowed to use popups. | Rationale: | Popup windows may be used to launch an attack within a new browser window
with altered settings. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-pop-up_windows | References: | | |
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Rule
Firefox private browsing must be disabled.
[ref] | Private browsing may be disabled in an administrative policy by setting
the DisablePrivateBrowsing key under policies to true . | Rationale: | Private browsing allows the user to browse the internet without recording their browsing history/activity. From a forensics perspective, this is unacceptable. Best practice requires that browser history is retained. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-private_browsing | References: | | |
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Rule
Firefox search suggestions must be disabled.
[ref] | Search Suggestions may be disabled in an administrative policy by setting
the SearchSuggestEnabled key under policies to false . | Rationale: | Search suggestions must be disabled as this could lead to searches being conducted that were never intended to be made. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-search_suggestion | References: | | |
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Rule
Disable Installed Search Plugins Update Checking
[ref] | Firefox automatically checks for updated versions of search plugins.
To disable the automatic updates of plugins, set value of
browser.search.update to false via policies.json. | Rationale: | Updates need to be controlled and installed from authorized and trusted servers.
This setting overrides a number of other settings which may direct the application
to access external URLs. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-search_update | References: | | |
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Rule
Firefox must be configured to allow only TLS 1.2 or above.
[ref] | Firefox may be configured via administrative policy to allow TLS 1.2 at minimum
by setting SSLVersionMin to tls1.2 . | Rationale: | Use of versions prior to TLS 1.2 are not permitted. SSL 2.0 and SSL 3.0 contain a number of security flaws.
These versions must be disabled in compliance with the Network Infrastructure and Secure Remote Computing STIGs. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-ssl_minimum_version | References: | | |
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Rule
Firefox accounts must be disabled.
[ref] | Firefox accounts feature may be disabled via administrative policy by setting
DisableFirefoxAccounts under policies to true . | Rationale: | Disable Firefox Accounts integration (Sync).
It is detrimental for applications to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors.
Applications are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions).
Examples of non-essential capabilities include but are not limited to advertising software or browser plug-ins that are not related to requirements or provide a wide array of functionality not required for every mission but that cannot be disabled. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-sync | References: | | |
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Rule
Disable Firefox Telemetry
[ref] | Telemetry can be disabled by setting
toolkit.telemetry.enabled to false . | Rationale: | The Telemetry feature provides this capability by sending performance and usage info to Mozilla. As you use Firefox, Telemetry measures and collects non-personal information, such as performance, hardware, usage and customizations. It then sends this information to Mozilla on a daily basis and we use it to improve Firefox | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-telemetry | References: | | |
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Rule
Firefox must not recommend extensions as the user is using the browser.
[ref] | The extension recommendation messages may be disabled in an administrative policy by setting
the ExtensionRecommendations key under UserMessaging to false . | Rationale: | The Recommended Extensions program recommends extensions to users as they surf the web.
The user must not be encouraged to install extensions from the websites they visit. Allowed extensions are to be centrally managed. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-user_messaging | References: | | |
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Rule
Enable Certificate Verification
[ref] | Firefox can be configured to prompt the user to choose a certificate
to present to a website when asked. To enable certificate verification,
set security.default_personal_cert to Ask Every Time
in an administrative policies file | Rationale: | Websites within DoD require user authentication for access which increases
security for DoD information. Access will be denied to the user if
certificate management is not configured. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_policy-verification | References: | | |
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Rule
Disable auto-download for proscribed MIME types.
[ref] | Firefox must be configured to not automatically execute or download MIME types that are not
authorized for auto-download. | Rationale: | This setting ensures that some file types that may be downloaded or executed without user interaction
are not downloaded and/or executed. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_firefox_preferences-auto-download_actions | References: | | |
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Rule
Supported Version of Firefox Installed
[ref] | If the system is joined to the Red Hat Network, a Red Hat Satellite Server,
or a yum server, run the following command to install updates:
$ sudo yum update
If the system is not configured to use one of these sources, updates (in the form of RPM packages)
can be manually downloaded and installed using rpm . | Rationale: | Use of versions of an application which are not supported by the vendor
are not permitted. Vendors respond to security flaws with updates and
patches. These updates are not available for unsupported version which
can leave the application vulnerable to attack. | Severity: | high | Rule ID: | xccdf_org.ssgproject.content_rule_installed_firefox_version_supported | References: | | |
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