June 2006

ID: 00438
Ref: 425/2006
Date: 23 June 2006:13:28:28
Version: 1

---

Title: Cisco Security Response: Document ID: 70509 - RealVNC Remote Authentication Bypass Vulnerability
Abstract:
Vendors affected: Cisco
Operating systems affected: Cisco
Applications affected: Cisco

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Title
=====

Cisco Security Response: Document ID: 70509 - RealVNC Remote Authentication Bypass
Vulnerability

Detail
======

RealVNC is a remote control access product that is bundled with Cisco
CallManager to provide remote console access.
A vulnerability in RealVNC may allow a malicious user to bypass RealVNC
authentication to gain console access to a Cisco CallManager system.


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Cisco Security Response: RealVNC Remote Authentication Bypass Vulnerability

Document ID: 70509

http://www.cisco.com/warp/public/707/cisco-sr-20060622-cmm.shtml

Revision 1.0

For Public Release 2006 June 22 1530 UTC (GMT)

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Contents
========

Cisco Response
Additional Information
Revision History
Cisco Security Procedures

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Cisco Response
==============

This is Cisco PSIRT's response to the CERT advisory
http://www.kb.cert.org/vuls/id/117929 and acknowledged by
Real VNC at http://www.realvnc.com/products/free/4.1/release-notes.html
This vulnerability was originally discovered by James Evans.

The original CERT advisory is available at
http://www.kb.cert.org/vuls/id/117929

This issue is being tracked by Cisco bug ID:

* CSCse32811 RealVNC allows remote access to Windows 2000 server
console without password.

Additional Information
======================

RealVNC is a remote control access product that is bundled with Cisco
CallManager to provide remote console access.

A vulnerability in RealVNC may allow a malicious user to bypass RealVNC
authentication to gain console access to a Cisco CallManager system.

In the event that a malicious user exploits this vulnerability to gain
access to a Cisco CallManager server, all normal CallManager and
Windows 2000 security will still apply and is intact. While this
vulnerability may provide remote access to a CallManager system, an
attacker will still require Windows and CallManager credentials to
further any attack.

RealVNC has resolved this vulnerability in software version 4.1.2 and
later.

Cisco has made available an update which will update RealVNC to version
4.1.2 and later and is available in CallManager update
win-OS-Upgrade-K9.2000-4-2sr8.exe which may be downloaded at
http://www.cisco.com/pcgi-bin/tablebuild.pl/cmva-3des

Workaround
==========

The workaround to this issue is to disable the RealVNC service. Please
consult RealVNC documentation for further details at
http://www.realvnc.com/documentation.html

THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY
KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE
INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT
YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS
DOCUMENT AT ANY TIME.

Revision History
================

+----------------------------------------+
| Revision | | Initial |
| 1.0 | 2006-June-22 | public |
| | | release. |
+----------------------------------------+

Cisco Security Procedures
=========================

Complete information on reporting security vulnerabilities in Cisco
products, obtaining assistance with security incidents, and registering
to receive security information from Cisco, is available on Cisco's
worldwide website at
http://www.cisco.com/warp/public/707/sec_incident_response.shtml.
This includes instructions for press inquiries regarding Cisco security
notices. All Cisco security advisories are available at
http://www.cisco.com/go/psirt.

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All contents are Copyright 1992-2006 Cisco Systems, Inc. All rights
reserved.
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Updated: Jun 22, 2006 Document ID: 70509

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