The alias file must have mode 0644 or less permissive.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-832	GEN004380	SV-63637r2_rule		Medium

Description
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.

STIG	Date
Oracle Linux 5 Security Technical Implementation Guide	2020-02-25

Details

Check Text ( C-52315r3_chk )
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 an alias file has a mode more permissive than 0644, 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 an alias file has a mode more permissive than 0644, this is a finding.

Check Text ( C-52315r3_chk )

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 an alias file has a mode more permissive than 0644, 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 an alias file has a mode more permissive than 0644, this is a finding.

Fix Text (F-54323r2_fix)
Change the mode of the alias files as needed to function. No higher than 0644. Procedure: for sendmail: # chmod 0644 /etc/aliases /etc/aliases.db for postfix (assuming the default postfix directory): # chmod 0644 /etc/postfix/aliases /etc/postfix/aliases