Vulnerability Assessment & Network Security Forums

If through a vulnerability assessment, a network security issue is detected for the vulnerability below, applying the appropriate security patches in a timely matter is very important. If you have detected that your system has already been compromised, following CERT's Network Security recovery document will assist with recommended steps for system recovery.

Home >> Browse Vulnerability Assessment Database >> Red Hat Local Security Checks >> RHSA-2002-287: vnc

Vulnerability Assessment Details

RHSA-2002-287: vnc

Vulnerability Assessment Summary
Check for the version of the vnc packages

Detailed Explanation for this Vulnerability Assessment

Updated VNC packages are available to fix a challenge replay attack that is
present in the VNC server.

VNC is a tool for providing a remote graphical user interface.

The VNC DES authentication scheme is implemented using a challenge-response
architecture, producing a random and different challenge for each
authentication attempt.

A bug in the function for generating the random challenge caused the random
seed to be reset to the current time on every authentication attempt.
As a result, two authentication attempts within the same second could
receive the same challenge. An eavesdropper could exploit this
vulnerability by replaying the response, thereby gaining authentication.

All users of VNC are advised to upgrade to these errata packages, which
contain an updated version and are not vulnerable to this issue.

Note that when using VNC on an untrusted network, always make sure to
tunnel the VNC protocol through a secure, authenticated channel such as
SSH. Instructions on how to tunnel VNC through SSH are provided at the
following URL: http://www.uk.research.att.com/vnc/sshvnc.html

Solution : http://rhn.redhat.com/errata/RHSA-2002-287.html
Network Security Threat Level: High

Networks Security ID:

Vulnerability Assessment Copyright: This script is Copyright (C) 2004 Tenable Network Security

Cables, Connectors