Mac OS X 10.3 Panther Screen Lock Bypass
Advisory Title: Keys Getting Past Panther Screen Lock
Release Date: 2003 October 28
Affected Product: Mac OS X 10.3 Build 7B85
Impact: Security Bypass
Where: Local System
Author: CodeSamurai (firstname.lastname@example.org)
With access to the keyboard, an unauthorized user can access the
currently active screen-locked user environment. However, there is
only a relatively small opening in the period of time in which the keys
events get through; completing complicated operations at the keyboard
have shown to be highly tedious in actual practice thus far.
With the screen effect active, keys pressed before the authentication
window appears will be sent to the general user environment.
- An open word processing document can be typed in.
- Shortcut operations via the keyboard are executed.
- New windows can be spawned.
- New folders can be created in the Finder.
- Switching between running applications is possible.
- One can navigate through the file system and launch applications.
- Terminal was launched and binary was executed from the command line.
Although the potential risk due to malicious intent via this
vulnerability is obvious, tentatively it appears that in real-world
practicality, the impact will most likely be statistically small. (But
a chain is only as strong as its weakest link.)
SecureMac Notes: For the first-time-user actually executing
anything useful before the screen lock appears is hard. For the user who practices and knows
where items are stored and can quickly move around with the keys could
change information or even disable authentication and gain access to the
Outside of the advisory, another major concern is that the user types
their password before the dialog box has appeared and it echos to
whatever application is parent in plain text. Instant Messages is what
users are reporting they have echo'd their passwords to accidently.
Could not connect!