USN-184-1: umount vulnerability

Publication date

19 September 2005

Overview

umount vulnerability

Releases


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.

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.

Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
5.04 hoary mount – 
4.10 warty mount – 

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