Title

The aliases file must be group-owned by root, sys, bin, or system. (Cat II impact)

Discussion

If the alias file is not group-owned by root or a system group, an unauthorized user may modify the file adding aliases to run malicious code or redirect e-mail.

Check Content

If the “sendmail” or “postfix” packages are not installed, this is not applicable. Check the group ownership of the alias files. Procedure: for sendmail: # ls -lL /etc/aliases If the file is not group-owned by root, this is a finding. # ls -lL /etc/aliases.db If the file is not group-owned by root, this is a finding. for postfix: Verify the location of the alias file. # postconf alias_maps This will return the location of the "aliases" file, by default "/etc/aliases". # ls -lL <postfix aliases file> If the file is not group-owned by root, this is a finding. # ls -lL <postfix aliases.db file> If the file is not group-owned by root, this is a finding.

Fix Text

Change the group-owner of the /etc/aliases file. Procedure: for sendmail: # chgrp root /etc/aliases # chgrp root /etc/aliases.db for postfix # chgrp root <postfix aliases file> # chgrp root <postfix aliases.db file>

Additional Identifiers

Rule ID: SV-45848r2_rule

Vulnerability ID: V-22438

Group Title: GEN004370

Expert Comments

CCIs tied to check.

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