4.4.1.3 NIS - remove NIS markers from password and group files

Information

If NIS has been de-installed in the environment, or has historically been used, ensure the + markers are removed from/etc/passwd and /etc/group.

Rationale:

The + entries in /etc/passwd and /etc/group were used as markers to insert data from a NIS map. These entries may provide an avenue for attackers to gain privileged access on the system. The + entries must be deleted if they still exist.

Solution

Examine the /etc/passwd and /etc/group files:

grep '^+' /etc/passwd /etc/group

If the above command yields output, delete the + line:

vi /etc/passwd
vi /etc/group

Default Value:

N/A

Additional Information:

Reversion:

Add the + line back to the same point in the file/s:

vi /etc/passwd

vi /etc/group

See Also

https://workbench.cisecurity.org/benchmarks/13069

Item Details

Category: IDENTIFICATION AND AUTHENTICATION

References: 800-53|IA-2

Plugin: Unix

Control ID: 9da5a0314ddb1878edfc6b2f4fe39ae3bfa5f2d004741f37a6eff4970e8eb6f2