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Ensure shadow Group is Empty

An XCCDF Rule

Description

The shadow group allows system programs which require access the ability to read the /etc/shadow file. No users should be assigned to the shadow group.

warning alert: Warning

This rule remediation will ensure the group membership is empty in /etc/group. To avoid any disruption the remediation won't change the primary group of users in /etc/passwd if any user has the shadow GID as primary group.

Rationale

Any users assigned to the shadow group would be granted read access to the /etc/shadow file. If attackers can gain read access to the /etc/shadow file, they can easily run a password cracking program against the hashed passwords to break them. Other security information that is stored in the /etc/shadow file (such as expiration) could also be useful to subvert additional user accounts.

ID
xccdf_org.ssgproject.content_rule_ensure_shadow_group_empty
Severity
Medium
References
Updated



Remediation - Shell Script


sed -ri 's/(^shadow:[^:]*:[^:]*:)([^:]+$)/\1/' /etc/group