x11vnc: Authentication bypass in included LibVNCServer code

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200608-12 / x11vnc
Release Date	August 07, 2006
Latest Revision	August 07, 2006: 01
Impact	high
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
x11-misc/x11vnc	< 0.8.1	>= 0.8.1	All supported architectures

Related bugreports: #142559

Synopsis

VNC servers created with x11vnc accept insecure protocol types, even when the server does not offer it, resulting in the possibility of unauthorized access to the server.

2. Impact Information

Background

x11vnc provides VNC servers for X displays.

Description

x11vnc includes vulnerable LibVNCServer code, which fails to properly validate protocol types effectively letting users decide what protocol to use, such as "Type 1 - None" (GLSA-200608-05). x11vnc will accept this security type, even if it is not offered by the server.

Impact

An attacker could exploit this vulnerability to gain unauthorized access with the privileges of the user running the VNC server.

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All x11vnc users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=x11-misc/x11vnc-0.8.1"

4. References

Page updated August 07, 2006

Summary: This is a Gentoo Linux Security Advisory

Security Team
Contact Address

Donate to support our development efforts.