Title

"At" jobs must not set the umask to a value less restrictive than 077. (Cat II impact)

Discussion

The umask controls the default access mode assigned to newly created files. An umask of 077 limits new files to mode 700 or less permissive. Although umask is often represented as a 4-digit number, the first digit representing special access modes is typically ignored or required to be 0.

Check Content

Determine what at jobs exist on the system. Procedure: # ls /var/spool/cron/atjobs If there are no at jobs present, this is not applicable. Determine if any of the at jobs or any scripts referenced execute the umask command. Check for any umask setting more permissive than 077. # grep -n umask <at job or referenced script> If any at job or referenced script sets umask to a value more permissive than 077, this is a finding. NOTE: The at facility will set the execution environment umask to 022. A grep of the at file will normally yield a line in the file that may look like umask 2. When examining any at job command file, this should not be mistaken for a user defined umask (re-)setting.

Fix Text

Edit at jobs or referenced scripts to remove umask commands setting the umask value more permissive than 077.

Additional Identifiers

Rule ID: SV-34996r1_rule

Vulnerability ID: V-4366

Group Title: GEN003440

Expert Comments

CCIs tied to check.

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