KDM: Local privilege escalation

Security Team  Contact Address

Updated October 14, 2007

1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200710-15 / KDM
Release Date October 14, 2007
Latest Revision October 14, 2007: 01
Impact high
Exploitable local
Package Vulnerable versions Unaffected versions Architecture(s)
kde-base/kdm < 3.5.7-r2 >= 3.5.7-r2 All supported architectures
kde-base/kdebase < 3.5.7-r4 >= 3.5.7-r4 All supported architectures

Related bugreports: #192373

Synopsis

KDM allows logins without password under certain circumstances allowing a local user to gain elevated privileges.

2.  Impact Information

Background

KDM is the Display Manager for the graphical desktop environment KDE. It is part of the kdebase package.

Description

Kees Huijgen discovered an error when checking the credentials which can lead to a login without specifying a password. This only occurs when auto login is configured for at least one user and a password is required to shut down the machine.

Impact

A local attacker could gain root privileges and execute arbitrary commands by logging in as root without specifying root's password.

3.  Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All KDM users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=kde-base/kdm-3.5.7-r2"

All kdebase users should upgrade to the latest version:

Code Listing 3.2: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=kde-base/kdebase-3.5.7-r4"

4.  References