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RE: Cisco Security Advisory: Cisco VPN3000Concentrator Vulnerable to Crafted HTTP Attack
From: "Dario Ciccarone (dciccaro)" <dciccaro () cisco com>
Date: Thu, 26 Jan 2006 13:43:17 -0500

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James:

        Dario Ciccarone from the Cisco PSIRT here.

        Each and every Cisco Security Advisory includes a section
entitled "Obtaining Fixed Software". Under that heading there are three
subsections - one for customers holding a service contract with Cisco,
another for customers with service contracts through third party
organizations, and the last one for those customers that don't fall into
either one of the previous two - "Customers without Service Contracts".

        It looks like your case would fall into that third category. If
that is the case, there are instructions on the Security Advisory on how
to contact the Cisco Technical Assistance Center ("TAC") in order to get
a free upgrade to the first fixed software version. The link to that
section, for this specific Advisory, is as follows:

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

        And as stated on the 'Summary' section of this Advisory (and
quoting):

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

        Link to that section is as follows:
        
http://www.cisco.com/warp/public/707/cisco-sa-20060126-vpn.shtml#summary

        So, in closing, you are not 'plain out of luck' - there is a
process in place for you to be able to obtain a fixed software release,
for free, even without a service contract.

        We appreciate feedback from customers and the community at large
on our public Security Advisories. Please feel free to contact us again
should the need arise. Our contact information can be found at:

        
http://www.cisco.com/en/US/products/products_security_vulnerability_poli
cy.html

        Thanks,
        Dario

-----Original Message-----
From: full-disclosure-bounces () lists grok org uk 
[mailto:full-disclosure-bounces () lists grok org uk] On Behalf 
Of James Lay
Sent: Thursday, January 26, 2006 1:01 PM
To: full-disclosure () lists grok org uk
Subject: RE: [Full-disclosure] Cisco Security Advisory: Cisco 
VPN3000Concentrator 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 () lists grok org uk
[mailto:full-disclosure-bounces () lists grok org uk] On Behalf Of Cisco
Systems Product Security Incident Response Team
Sent: Thursday, January 26, 2006 10:00 AM
To: full-disclosure () lists grok org uk
Cc: psirt () cisco com
Subject: [Full-disclosure] Cisco Security Advisory: Cisco VPN
3000Concentrator Vulnerable to Crafted HTTP Attack

WARNING: Unsanitized content follows.
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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 () cisco com" or "security-alert () cisco 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 () cisco 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 () cisco com
  * first-teams () first org
  * bugtraq () securityfocus com
  * vulnwatch () vulnwatch org
  * cisco () spot colorado edu
  * cisco-nsp () puck nether net
  * full-disclosure () lists grok org uk
  * comp.dcom.sys.cisco () newsgate 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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_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

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_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/


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