Title

The /etc/shells (or equivalent) file must exist. (Cat II impact)

Discussion

The shells file (or equivalent) lists approved default shells. It helps provide layered defense to the security approach by ensuring users cannot change their default shell to an unauthorized shell that may not be secure.

Check Content

Verify /etc/shells exists. # ls -l /etc/shells If the file does not exist, this is a finding.

Fix Text

Create a /etc/shells file containing a list of valid system shells. Consult vendor documentation for an appropriate list of system shells. Procedure: # echo "/bin/bash" >> /etc/shells # echo "/bin/csh" >> /etc/shells (Repeat as necessary for other shells.)

Additional Identifiers

Rule ID: SV-916r2_rule

Vulnerability ID: V-916

Group Title: GEN002120

Expert Comments

CCIs tied to check.

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