umount vulnerability

Releases

• Ubuntu 5.04
• Ubuntu 4.10

Details

David Watson discovered that “umount -r” removed some restrictive
mount options like the “nosuid” flag. If /etc/fstab contains
user-mountable removable devices which specify the “nosuid” flag
(which is common practice for such devices), a local attacker could
exploit this to execute arbitrary programs with root privileges by
calling “umount -r” on a removable device.

This does not affect the default Ubuntu configuration. Since Ubuntu
mounts removable devices automatically, there is normally no need to
configure them manually in /etc/fstab.