The alias file must not have an extended ACL.

From Oracle Linux 5 Security Technical Implementation Guide

Associated with: CCI-000225

SV-63643r1_rule The alias file must not have an extended ACL.

Vulnerability 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 e-mail.

Check content

If the "sendmail" and "postfix" packages are not installed, this is not applicable. Check the permissions of the alias file. Procedure: for sendmail: # ls -lL /etc/aliases /etc/aliases.db If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, 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/postfix/aliases" # ls -lL If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix text

Remove the extended permissions from the alias files. Procedure: for sendmail: # setfacl --remove-all /etc/aliases /etc/aliases.db for postfix (assuming the default postfix directory): # setfacl --remove-all /etc/postfix/aliases /etc/postfix/aliases.db

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