The authselect package can be installed with the following command:
$ apt-get install authselect
The authselect package provides a tool to select system authentication and identity sources from a list of supported profiles instead of letting the administrator manually build the PAM stack. Authselect is a successor to authconfig and helps avoid potential breakage of configuration by shipping several tested profiles that are well tested and supported. Ensuring the latest version of authselect is installed helps maintain system security by providing the latest security fixes and features.