Title

The alias file must not have an extended ACL. (Cat II impact)

Discussion

Excessive permissions on the aliases file may permit unauthorized modification. If the alias file is modified by an unauthorized user, they may modify the file to run malicious code or redirect email.

Check Content

Note: If sendmail is not installed, this requirement is not applicable. Find the alias files on the system. Procedure: # egrep '^O(A| AliasFile)' /etc/mail/sendmail.cf If the "alias file" is an NIS or LDAP map, this check is not applicable. The default location is /etc/mail/aliases. Check the permissions of the alias file and the hashed version of it used by sendmail. Procedure: # ls -lL /etc/mail/aliases /etc/mail/aliases.db If the permissions include a "+", the file has an extended ACL and this is a finding.

Fix Text

Remove the extended ACL from the files. # chmod A- /etc/mail/aliases /etc/mail/aliases.db

Additional Identifiers

Rule ID: SV-227839r858559_rule

Vulnerability ID: V-227839

Group Title: SRG-OS-000480

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.