cdrtools: Local root vulnerability in cdrecord if set SUID root

Background

The cdrtools package is a set of tools for CD recording, including the popular cdrecord command-line utility.

Description

Max Vozeler discovered that the cdrecord utility, when set to SUID root, fails to drop root privileges before executing a user-supplied RSH program. By default, Gentoo does not ship the cdrecord utility as SUID root and therefore is not vulnerable. However, many users (and CD-burning front-ends) set this manually after installation.

Impact

A local attacker could specify a malicious program using the $RSH environment variable and have it executed by the SUID cdrecord, resulting in root privileges escalation.

Workaround

As a workaround, you could remove the SUID rights from your cdrecord utility :

# chmod a-s /usr/bin/cdrecord

Resolution

All cdrtools users should upgrade to the latest version:

 # emerge sync

 # emerge -pv ">=app-cdr/cdrtools-2.01_alpha37-r1"
 # emerge ">=app-cdr/cdrtools-2.01_alpha37-r1"