How secure is XScreenSaver against physical attacks
We use LUKS/dm-crypt encrypted workstations with long passwords.
But if an laptop is unlocked and booted into Debian, using Xscreensaver then the disk is in an unencrypted state but the keyboard is locked.
My question is, would it be possible to with full physical local access, on a normal laptop to bypass the screensaver and enter the OS as the logged in user?
The scenario would be someone stealing the laptop that has FDE but the user being logged on and the screen locked (lid-closed default state)
I guess for example that one could use advanced hardware techniques such as Fault Injection, but there might be other ways to force entry?
Another follow up question is how to protect a laptop from physical access without turning it off or otherwise severely affecting boot-up time to continue working, for example in a café/train enviroment.
