3.5.1.3 NIS - remove NIS markers from password and group files - /etc/passwd

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/files/4119

Item Details

Category: AUDIT AND ACCOUNTABILITY, SYSTEM AND INFORMATION INTEGRITY

References: 800-53|AU-3, 800-53|SI-4, CSCv7|4.8, CSCv7|9.2

Plugin: Unix

Control ID: c6c028763d3769895ec845c92ce1d0f863ce83f4b53c315eb365ed2f05307943