How to disable the guest account in Oneiric

Ubuntu 11.10 now ships with the guest account available at the LightDM login screen.

This new feature isn't really a security issue, since by default using it requires physical access, and it is confined with an AppArmor profile. If an attacker has physical access to your laptop, all bets are off.

The guest account can be disabled by editing /etc/lightdm/lightdm.conf and adding "allow-guest=false" to the "SeatDefaults" section.