cyberstrikeus 6.1.5 Ensure permissions on /etc/shadow are configured (Automated)
Profile
- Level 1 - Server
- Level 1 - Workstation
Description
The /etc/shadow file is used to store the information about user accounts that is critical to the security of those accounts, such as the hashed password and other security information.
Rationale
If attackers can gain read access to the /etc/shadow file, they can easily run a password cracking program against the hashed password to break it. Other security information that is stored in the /etc/shadow file (such as expiration) could also be useful to subvert the user accounts.
Audit Procedure
Command Line
Run the following command to verify /etc/shadow is mode 640 or more restrictive, Uid is 0/root and Gid is 0/root or {GID}/shadow:
# stat -Lc 'Access: (%#a/%A) Uid: ( %u/ %U) Gid: ( %g/ %G)' /etc/shadow
Expected Result
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 42/ shadow)
Remediation
Command Line
Run one of the following commands to set ownership of /etc/shadow to root and group to either root or shadow:
# chown root:shadow /etc/shadow
-OR-
# chown root:root /etc/shadow
Run the following command to remove excess permissions from /etc/shadow:
# chmod u-x,g-wx,o-rwx /etc/shadow
Default Value
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 42/ shadow)
References
- NIST SP 800-53 Rev. 5: AC-3. MP-2
CIS Controls
- v8: 3.3 Configure Data Access Control Lists
- v7: 14.6 Protect Information through Access Control Lists