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

From Oracle Linux 5 Security Technical Implementation Guide

Associated with: CCI-000366

SV-63651r1_rule The /etc/shells (or equivalent) file must exist.

Vulnerability 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 unsecure shell.

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.)

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