Ensure no duplicate UIDs exist

How it is checked

Audit method: Shell command

alt0() { o=$(bash -c '#!/usr/bin/env bash

{
  while read -r l_count l_uid; do
    if [ "$l_count" -gt 1 ]; then
      echo -e "Duplicate UID: \"$l_uid\" Users: \"$(awk -F: '"'"'($3 == n) { print $1 }'"'"' n=$l_uid /etc/passwd | xargs)\""
    fi
  done < <(cut -f3 -d":" /etc/passwd | sort -n | uniq -c)
}' 2>&1); [ -z "$o" ] || { echo "step1: $o" | head -c 300; return 1; }; }; if alt0; then echo compliant; fi

Expected output

compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Based on the Audit Procedure output, for each UID shared by more than one account, keep the UID on the correct account and assign a new, unused UID to each of the other accounts: # usermod -u <UID> <username> usermod reassigns ownership of files in the account's home directory automatically. Review any other files owned by the previously shared UID and reassign ownership to the correct account as appropriate.

Check this host

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

tmaegis scan --target linux