Ensure no duplicate user names exist

MediumLevel 1Automatedfreebsd

Description

Although the adduser or pw program will not let you create a duplicate user name, it is possible for an administrator to manually edit the /etc/passwd file and change the username. If a user is assigned a duplicate user name, it will create and have access to files with the first UID for that username in /etc/passwd. Audit: automated read-only check derived from the CIS audit procedure; it prints "compliant" when the control is met.

How it is checked

Audit method: Shell command

shell

command -v cut >/dev/null 2>&1 || exit 1; out=$( { cut -d: -f1 /etc/passwd | sort | uniq -d ; } 2>/dev/null ); [ -z "$out" ] && echo compliant || printf '%s\n' "$out" | head -n 20

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Establish unique user names for the users based on the audit script's results. As long as the users have unique UIDs, file ownership will automatically reflect the change.

Properties

Operating systems: Any
Tags: freebsdaccounts
Reference: CIS FreeBSD 14 Benchmark v1.0.1 - 6.2.6 Ensure no duplicate user names exist

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell

tmaegis scan --target freebsd