Detections
Analytics
7.2.6 Ensure no duplicate user names exist
Information
Although the useradd 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 . For example, if "test4" has a UID of 1000 and a subsequent "test4" entry has a UID of 2000, logging in as "test4" will use UID 1000. Effectively, the UID is shared, which is a security problem.
Solution
Based on the Audit Procedure output, for each duplicated user name, determine which entry is correct and make each user name unique. Use vipw to safely edit the user database and either remove the redundant entry or rename it to a unique user name:# vipw
File ownerships will reflect the change automatically as long as each account has a unique UID.
See Also
Item Details
Category: IDENTIFICATION AND AUTHENTICATION
References: 800-53|IA-2
Plugin: Unix
Control ID: 83100b8aebe886ac954001ebafbd5a5fb77d3e41e71a3e7e74ca37612cc31dc1