6.2.18 Ensure no duplicate user names exist

Information

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 results of the audit script, establish unique user names for the users. File ownerships will automatically reflect the change as long as the users have unique UIDs.

See Also

https://workbench.cisecurity.org/files/1863

Item Details

Category: IDENTIFICATION AND AUTHENTICATION

References: 800-53|IA-4d., CSCv6|16

Plugin: Unix

Control ID: 9f61bbc6c2f3437a9440c2c04c86f8c8e7932e332c355aeda6c6f5d2bc15bf7c