LTSP: Authentication bypass in included LibVNCServer code

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200703-19 / ltsp
Release Date	March 18, 2007
Latest Revision	March 18, 2007: 01
Impact	high
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
net-misc/ltsp	< 4.2-r1	>= 4.2-r1	All supported architectures

Related bugreports: #142661

Synopsis

LTSP includes a version of libVNCServer that is vulnerable to an authentication bypass.

2. Impact Information

Background

The Linux Terminal Server Project adds thin-client support to Linux servers.

Description

The LTSP server 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). The LTSP VNC server 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 LTSP users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/ltsp-4.2-r1"

4. References

Page updated March 18, 2007

Summary: This is a Gentoo Linux Security Advisory

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