sudo: Privilege escalation

Background

sudo (su “do”) allows a system administrator to delegate authority to give certain users (or groups of users) the ability to run some (or all) commands as root or another user while providing an audit trail of the commands and their arguments.

Description

Qualys discovered a vulnerability in sudo’s get_process_ttyname() for Linux, that via sudo_ttyname_scan() can be directed to use a user-controlled, arbitrary tty device during its traversal of “/dev” by utilizing the world-writable /dev/shm.

For further information, please see the Qualys Security Advisory

Impact

A local attacker can pretend that his tty is any character device on the filesystem, and after two race conditions, an attacker can pretend that the controlled tty is any file on the filesystem allowing for privilege escalation

Workaround

There is no known workaround at this time.

Resolution

All sudo users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=app-admin/sudo-1.8.20_p1"