cis-ubuntu1804-v220-1-7-4

DevOps & Security

Ensure permissions on /etc/motd are configured

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1.7.4 Ensure permissions on /etc/motd are configured (Automated)

Profile Applicability

Level 1 - Server
Level 1 - Workstation

Description

The contents of the /etc/motd file are displayed to users after login and function as a message of the day for authenticated users.

Rationale

If the /etc/motd file does not have the correct ownership it could be modified by unauthorized users with incorrect or misleading information.

Audit Procedure

Command Line

Run the following command and verify that if /etc/motd exists, Access is 644 or more restrictive, Uid and Gid are both 0/root:

[ -e /etc/motd ] && stat -Lc 'Access: (%#a/%A) Uid: ( %u/ %U) Gid: ( %g/ %G)' /etc/motd

Expected Result

Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
  -- OR --
Nothing is returned

Remediation

Command Line

Run the following commands to set permissions on /etc/motd:

chown root:root $(readlink -e /etc/motd)
chmod u-x,go-wx $(readlink -e /etc/motd)

-- OR --

Run the following command to remove the /etc/motd file:

rm /etc/motd

Default Value

File doesn't exist

Additional Information

If Message of the day is not needed, this file can be removed.

References

NIST SP 800-53 Rev. 5: AC-3, MP-2

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	3.3 Configure Data Access Control Lists	X	X	X
v7	14.6 Protect Information through Access Control Lists	X	X	X

MITRE ATT&CK Mappings

Techniques / Sub-techniques	Tactics	Mitigations
T1222, T1222.002	TA0005	M1022