‘Mac OS 9 Multiple Users Control Panel password vulnerability’


‘Mac OS 9.04 comes with a ‘Multiple Users’ Control Panel that allows an administrator (called ‘Owner’) to create user accounts (called ‘Normal’ users) with limited access to the computer.

The problem is that the Owner password can be removed by a Normal user by moving the ‘Users & Groups Data File and logging back in using the Owner account, giving full access to the machine.’


‘The information has been provided by Todd Kirby.’


Vulnerable systems:
Mac G3 and G4 with OS 9.04.

Log in as a Normal user. Find the file called ‘Users & Groups Data File’ in the Preferences Folder and move it to another location. Log out and back in using the Owner account.

Result: No password is required to log in as the Owner user. User now has full access to the computer, including the ability to make changes in the ‘Multiple Users’ control panel.

The previously moved ‘Users & Groups Data File’ can be moved back into the Preferences folder to restore the original Owner password making detection difficult.

Use ‘Limited’ instead of ‘Normal’ when setting up user accounts. This will protect the Preferences folder from being altered.

The problem has been fixed by Apple in Macintosh Manager 1.4. See the following URLs for more information:

Categories: Exploits