Date: Thu Jan 26 18:00:58 2006
From: jlay at slave-tothe-box.net (James Lay)
Subject: Cisco Security Advisory: Cisco VPN
	3000Concentrator Vulnerable to Crafted HTTP Attack

So just for fun, I decided to attempt to get this file with my "guest
access".  No go....so apparently if I don't have a "Cisco Service
Agreement", I'm just plain out of luck...even Microsoft has free security
updates.  Get with it Cisco. 

-----Original Message-----
From: full-disclosure-bounces@...ts.grok.org.uk
[mailto:full-disclosure-bounces@...ts.grok.org.uk] On Behalf Of Cisco
Systems Product Security Incident Response Team
Sent: Thursday, January 26, 2006 10:00 AM
To: full-disclosure@...ts.grok.org.uk
Cc: psirt@...co.com
Subject: [Full-disclosure] Cisco Security Advisory: Cisco VPN
3000Concentrator Vulnerable to Crafted HTTP Attack

WARNING: Unsanitized content follows.
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Hash: SHA1

Cisco Security Advisory: Cisco VPN 3000 Concentrator Vulnerable to Crafted
HTTP Attack

Advisory ID: cisco-sa-20060126-vpn

http://www.cisco.com/warp/public/707/cisco-sa-20060126-vpn.shtml

Revision 1.0

For Public Release 2006 January 26 1700 UTC (GMT)

+--------------------------------------------------------------------

Contents
========

    Summary
    Affected Products
    Details
    Impact
    Software Versions and Fixes
    Workarounds
    Obtaining Fixed Software
    Exploitation and Public Announcements
    Status of This Notice: FINAL
    Distribution
    Revision History
    Cisco Security Procedures

+--------------------------------------------------------------------

Summary
=======

The Cisco VPN 3000 series concentrators are a family of purpose-built,
remote access Virtual Private Network (VPN) platforms for data encryption
and authentication.

A malicious user may be able to send a crafted HTTP (Hypertext Transfer
Protocol) packet to the concentrators which may cause the device to reload
and drop user connections.

Repeated exploitation of this vulnerability will create a sustained DoS
(denial of service).

Cisco has made free software available to address this vulnerability for
affected customers. There are workarounds available to mitigate this
vulnerability as well.

This advisory is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20060126-vpn.shtml

Affected Products
=================

Vulnerable Products
+------------------

Cisco VPN 3000 series concentrators running software 4.7.0 through 4.7.2.A
are affected by this vulnerability. This includes version 4.7REL. Software
versions prior to 4.7.x are not vulnerable.

This series includes models 3005, 3015, 3020, 3030, 3060, and the 3080.

Products Confirmed Not Vulnerable
+--------------------------------

The following products are confirmed not vulnerable:

  * Cisco VPN 3002 Hardware Client
  * Cisco IPSec VPN Services Module (VPNSM)
  * Cisco VPN 5000 Concentrators
  * Cisco PIX Firewalls
  * Cisco Adaptive Security Appliance (ASA)
  * Any Cisco device that runs Cisco's Internetwork Operating System
    (IOS)
  * Any Cisco device that runs Cisco's Catalyst Operating System
    (CatOS)

No other Cisco products are currently known to contain this vulnerability.

Details
=======

Hypertext Transfer Protocol (HTTP) is a set of rules for exchanging files
(text, graphic images, sound, video, and other multimedia
files) on the World Wide Web. HTTP is an application protocol for which the
default TCP port is 80. Due to this vulnerability, a malicious user may send
crafted HTTP packets which may result in a reload of the affected device
and/or user connections being dropped.

The affected products are only vulnerable if they have the HTTP service
enabled. By default, HTTP is enabled on VPN 3000 devices, however it may be
manually disabled. Affected devices are not vulnerable to transit traffic,
only traffic that is destined to them may exploit this vulnerability.

To check if the HTTP service is enabled, please do the following:

 1. Check the configuration on the device to verify the status of the
    HTTP service.
 2. Try to connect to the device using a standard web browser that
    supports using a URL similar to http://ip_address_of_device/.

This vulnerability is documented in the Cisco Bug Toolkit as Bug ID
CSCsb77324. 

Impact
======

Successful exploitation of this vulnerability may result in a reload of the
affected device and user connections being dropped.

Repeated exploitation of this vulnerability could result in a sustained
Denial of Service.

Software Versions and Fixes
===========================

Cisco VPN 3000 series software version 4.7.2.B and later is not vulnerable.

Cisco VPN 3000 series users can upgrade to version 4.7.2.B or later software
to resolve this vulnerability. Cisco VPN 3000 software is available for
download at http://www.cisco.com/cgi-bin/tablebuild.pl/vpn3000-3des

When considering software upgrades, also consult
http://www.cisco.com/go/psirt and any subsequent advisories to determine
exposure and a complete upgrade solution.

In all cases, customers should exercise caution to be certain the devices to
be upgraded contain sufficient memory and that current hardware and software
configurations will continue to be supported properly by the new release. If
the information is not clear, contact the Cisco Technical Assistance Center
(TAC) or your contracted maintenance provider for assistance.

Workarounds
===========

Disable HTTP
+-----------

Disabling HTTP will effectively mitigate this vulnerability.

With HTTP disabled, the concentrator can be configured to use HTTPS
(HyperText Transfer Protocol Secure) for both concentrator management and
WebVPN connectivity if WebVPN connectivity is configured on the
concentrator.

To implement this workaround, first enable HTTPS, then disable HTTP.

If WebVPN is used, it is important to also disable any HTTP proxys that may
be configured (HTTPS is always enabled for WebVPN if WebVPN is enabled)

For details on how to enable HTTPS management of the concentrator, please
reference:

http://www.cisco.com/en/US/products/hw/vpndevc/ps2284/
products_configuration_guide_chapter09186a00803ee1e4.html#wp1309312

For details on how to disable HTTP management of the concentrator, please
reference:

http://www.cisco.com/en/US/products/hw/vpndevc/ps2284/
products_configuration_guide_chapter09186a00803ee11f.html#wp999607

For details on how to disable WebVPN HTTP proxies please see:

http://www.cisco.com/en/US/products/hw/vpndevc/ps2284/
products_configuration_guide_chapter09186a00803ee1e4.html#wp1400335

Infrastructure ACLs
+------------------

HTTP to the VPN3000 could be blocked as part of a Infrastructure ACL on
screening routers, switches and firewalls controlling all access to the
trusted network. Infrastructure ACLs are considered a network security best
practice and should be considered as a long-term addition to good network
security, as well as a workaround for this specific vulnerability. The white
paper entitled "Protecting Your
Core: Infrastructure Protection Access Control Lists" presents guidelines
and recommended deployment techniques:

http://www.cisco.com/en/US/tech/tk648/tk361/
technologies_white_paper09186a00801a1a55.shtml

Obtaining Fixed Software
========================

Cisco has made free software available to address this vulnerability for
affected customers. Prior to deploying software, customers should consult
their maintenance provider or check the software for feature set
compatibility and known issues specific to their environment.

Customers may only install and expect support for the feature sets they have
purchased. By installing, downloading, accessing or otherwise using such
software upgrades, customers agree to be bound by the terms of Cisco's
software license terms found at
http://www.cisco.com/public/sw-license-agreement.html
or as otherwise set forth at Cisco.com Downloads at
http://www.cisco.com/public/sw-center/sw-usingswc.shtml

Do not contact either "psirt@...co.com" or "security-alert@...co.com"
for software upgrades.

Customers with Service Contracts
+-------------------------------

Customers with contracts should obtain upgraded software through their
regular update channels. For most customers, this means that upgrades should
be obtained through the Software Center on Cisco's worldwide website at
http://www.cisco.com.

Customers using Third-party Support Organizations
+------------------------------------------------

Customers whose Cisco products are provided or maintained through prior or
existing agreement with third-party support organizations such as Cisco
Partners, authorized resellers, or service providers should contact that
support organization for guidance and assistance with the appropriate course
of action in regards to this advisory.

The effectiveness of any workaround or fix is dependent on specific customer
situations such as product mix, network topology, traffic behavior, and
organizational mission. Due to the variety of affected products and
releases, customers should consult with their service provider or support
organization to ensure any applied workaround or fix is the most appropriate
for use in the intended network before it is deployed.

Customers without Service Contracts
+----------------------------------

Customers who purchase direct from Cisco but who do not hold a Cisco service
contract and customers who purchase through third-party vendors but are
unsuccessful at obtaining fixed software through their point of sale should
get their upgrades by contacting the Cisco Technical Assistance Center
(TAC). TAC contacts are as follows.

  * +1 800 553 2447 (toll free from within North America)
  * +1 408 526 7209 (toll call from anywhere in the world)
  * e-mail: tac@...co.com

Have your product serial number available and give the URL of this notice as
evidence of your entitlement to a free upgrade. Free upgrades for
non-contract customers must be requested through the TAC.

Refer to http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml
for additional TAC contact information, including special localized
telephone numbers and instructions and e-mail addresses for use in various
languages.

Exploitation and Public Announcements
=====================================

The Cisco PSIRT is not aware of any malicious use of the vulnerability
described in this advisory.

This issue was discussed at the Schmoocon security conference on January
12th, 2006.

Status of This Notice: FINAL
============================

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.

A stand-alone copy or Paraphrase of the text of this document that omits the
distribution URL in the following section is an uncontrolled copy, and may
lack important information or contain factual errors.

Distribution
============

This advisory is posted on Cisco's worldwide website at
http://www.cisco.com/warp/public/707/cisco-sa-20060126-vpn.shtml

In addition to worldwide web posting, a text version of this notice is
clear-signed with the Cisco PSIRT PGP key and is posted to the following
e-mail and Usenet news recipients.

  * cust-security-announce@...co.com
  * first-teams@...st.org
  * bugtraq@...urityfocus.com
  * vulnwatch@...nwatch.org
  * cisco@...t.colorado.edu
  * cisco-nsp@...k.nether.net
  * full-disclosure@...ts.grok.org.uk
  * comp.dcom.sys.cisco@...sgate.cisco.com

Future updates of this advisory, if any, will be placed on Cisco's worldwide
website, but may or may not be actively announced on mailing lists or
newsgroups. Users concerned about this problem are encouraged to check the
above URL for any updates.

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

+---------------------------------------+
| Revision |                 | Initial  |
| 1.0      | 26-January-2006 | 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/en/US/products/
products_security_vulnerability_policy.html
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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