The root account must be the only account having an UID of 0.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-773	GEN000880	SV-773r7_rule	ECLP-1	Medium

Description
If an account has an UID of 0, it has root authority. Multiple accounts with an UID of 0 afford more opportunity for potential intruders to guess a password for a privileged account.

STIG	Date
Draft AIX Security Technical Implementation Guide	2011-08-17

Details

Check Text ( C-28053r1_chk )
Check the system for duplicate UID 0 assignments by listing all accounts assigned UID 0. Procedure: # grep ":0:" /etc/passwd | awk -F":" '{print$1":"$3":"}' | grep ":0:" If any accounts other than root are assigned UID 0, this is a finding.

Fix Text (F-24403r1_fix)
Remove or change the UID of accounts other than root that have UID 0.