RE: Cisco Security Advisory: Cisco VPN3000Concentrator Vulnerable to Crafted HTTP Attack

["Dario Ciccarone (dciccaro)" <dciccaro () cisco com>]

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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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