Fwd: [Full-disclosure] Cisco Security Advisory: Firewall Services Module Crafted ICMP Message Vulnerability

John Kinsella jlk at thrashyour.com
Wed Aug 19 15:02:32 CDT 2009


FYI...I thought PSIRT sent security notices to nanog?

Begin forwarded message:

> From: Cisco Systems Product Security Incident Response Team <psirt at cisco.com 
> >
> Date: August 19, 2009 10:12:26 AM PDT
> To: full-disclosure at lists.grok.org.uk
> Cc: psirt at cisco.com
> Subject: [Full-disclosure] Cisco Security Advisory: Firewall  
> Services Module Crafted ICMP Message Vulnerability
>
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Cisco Security Advisory: Firewall Services Module Crafted ICMP Message
> Vulnerability
>
> Advisory ID: cisco-sa-20090819-fwsm
>
> http://www.cisco.com/warp/public/707/cisco-sa-20090819-fwsm.shtml
>
> Revision 1.0
>
> For Public Release 2009 August 19 1600 UTC (GMT)
>
> Summary
> =======
>
> A vulnerability exists in the Cisco Firewall Services Module (FWSM)  
> for
> the Catalyst 6500 Series Switches and Cisco 7600 Series Routers. The
> vulnerability may cause the FWSM to stop forwarding traffic and may be
> triggered while processing multiple, crafted ICMP messages.
>
> There are no known instances of intentional exploitation of this
> vulnerability. However, Cisco has observed data streams that appear to
> trigger this vulnerability unintentionally.
>
> Cisco has released free software updates that address this
> vulnerability.
>
> This advisory is posted at
> http://www.cisco.com/warp/public/707/cisco-sa-20090819-fwsm.shtml.
>
> Affected Products
> =================
>
> Vulnerable Products
> - -------------------
>
> All non-fixed 2.x, 3.x and 4.x versions of the FWSM software are
> affected by this vulnerability.
>
> To determine the version of the FWSM software that is running, issue
> the "show module" command-line interface (CLI) command from Cisco IOS
> Software or Cisco Catalyst Operating System Software to identify what
> modules and sub-modules are installed in the system.
>
> The following example shows a system with an FWSM (WS-SVC-FWM-1)
> installed in slot 4.
>
> switch#show module
> Mod Ports Card Type                              Model               
> Serial No.
> --- ----- -------------------------------------- -----------------  
> -----------
> 1   48    SFM-capable 48 port 10/100/1000mb RJ45 WS-X6548-GE-TX     
> SAxxxxxxxxx
> 4    6    Firewall Module                        WS-SVC-FWM-1       
> SAxxxxxxxxx
> 5    2    Supervisor Engine 720 (Active)         WS-SUP720-BASE     
> SAxxxxxxxxx
> 6    2    Supervisor Engine 720 (Hot)            WS-SUP720-BASE     
> SAxxxxxxxxx
>
> After locating the correct slot, issue the "show module <slot number>"
> command to identify the software version that is running.
>
> switch#show module 4
> Mod Ports Card Type                              Model               
> Serial No.
> --- ----- -------------------------------------- -----------------  
> -----------
> 4    6    Firewall Module                        WS-SVC-FWM-1       
> SAxxxxxxxxx
>
> Mod MAC addresses                     Hw     Fw            
> Sw           Status
> --- --------------------------------- ------ ------------  
> ------------ -------
> 4   0003.e4xx.xxxx to 0003.e4xx.xxxx  3.0    7.2(1)        
> 3.2(3)       Ok
>
> The preceding example shows that the FWSM is running software version
> 3.2(3) as indicated by the column under "Sw".
>
> Note: Recent versions of Cisco IOS Software will show the software
> version of each module in the output from the "show module" command;
> therefore, executing the "show module <slot number>" command is not
> necessary.
>
> If a Virtual Switching System (VSS) is used to allow two physical  
> Cisco
> Catalyst 6500 Series Switches to operate as a single logical virtual
> switch, the "show module switch all" command can display the software
> version of all FWSMs that belong to switch 1 and switch 2. The output
> from this command will be similar to the output from the "show module
> <slot number>" but will include module information for the modules in
> each switch in the VSS.
>
> Alternatively, version information can be obtained directly from the
> FWSM through the "show version" command, as shown in the following
> example.
>
>    FWSM#show version
>    FWSM Firewall Version 3.2(3)
>
> Customers who use the Cisco Adaptive Security Device Manager (ASDM) to
> manage their devices can find the version of the software displayed in
> the table in the login window or in the upper left corner of the ASDM
> window. The version notation is similar to the following example.
>
>    FWSM Version: 3.2(3)
>
> Products Confirmed Not Vulnerable
> - ---------------------------------
>
> Other Cisco products that offer firewall services, including Cisco IOS
> Software, Cisco ASA 5500 Series Adaptive Security Appliances, and  
> Cisco
> PIX Security Appliances, are not affected by this vulnerability.
>
> No other Cisco products are currently known to be affected by this
> vulnerability.
>
> Details
> =======
>
> The Cisco FWSM is a high-speed, integrated firewall module for  
> Catalyst
> 6500 Series Switches and Cisco 7600 Series Routers. The FWSM offers
> firewall services with stateful packet filtering and deep packet
> inspection.
>
> A vulnerability exists in the Cisco FWSM Software that may cause
> the FWSM to stop forwarding traffic between interfaces, or stop
> processing traffic that is directed at the FWSM (management traffic)
> after multiple, crafted ICMP messages are processed by the FWSM. Any
> traffic that transits or is directed towards the FWSM is affected,
> regardless of whether ICMP inspection ("inspect icmp" command under
> Class configuration mode) is enabled.
>
> The FWSM stops processing traffic because one of the Network  
> Processors
> (NPs) that is used by the FWSM to handle traffic may use all available
> execution threads while handling a specific type of crafted ICMP
> messages. This behavior limits the execution threads that are  
> available
> to handle additional traffic.
>
> Administrators may be able to determine if the FWSM has been affected
> by this vulnerability by issuing the "show np 2 stats" command. If  
> this
> command produces output showing various counters and their values, as
> shown in the example CLI output that follows, the FWSM has not been
> affected by the vulnerability. If the command returns a single line  
> that
> reads "ERROR: np_logger_query request for FP Stats failed", the FWSM  
> may
> have been affected by the vulnerability.
>
> FWSM#show np 2 stats
> -  
> -------------------------------------------------------------------------------
> Fast Path 64 bit Global Statistics Counters (NP-2)
>
> -  
> -------------------------------------------------------------------------------
> PKT_MNG: total packets (dot1q) rcvd                : 10565937
> PKT_MNG: total packets (dot1q) sent                : 4969517
> PKT_MNG: total packets (dot1q) dropped             : 65502
> PKT_MNG: TCP packets received                      : 0
> PKT_MNG: UDP packets received                      : 4963509
> PKT_MNG: ICMP packets received                     : 0
> PKT_MNG: ARP packets received                      : 2
> PKT_MNG: other protocol pkts received              : 0
> PKT_MNG: default (no IP/ARP) dropped               : 0
> SESS_MNG: sessions created                         : 18
> SESS_MNG: sessions embryonic to active             : 0
> [...]
>
> An FWSM that stops processing traffic as a result of this  
> vulnerability
> will need to be reloaded. Administrators can reload the FWSM from the
> supervisor of the Catalyst 6500 Series Switch or the Cisco 7600 Series
> Router by issuing the command "hw-module module <slot # for FWSM>  
> reset"
> (Cisco IOS Software), or "set module power up| down <module #>" (Cisco
> CatOS Software). Note that unless the FWSM software is updated to a
> non-vulnerable version, or crafted ICMP messages are blocked (see the
> Workarounds section for details), the FWSM can still be subject to
> exploitation (intentional or otherwise) after a reload.
>
> If an FWSM that is configured for failover operation encounters this
> issue, the active FWSM may not properly fail over to the standby FWSM.
>
> IPv6 (in particular ICMPv6) cannot trigger this vulnerability.
>
> This issue is documented in Cisco Bug ID CSCsz97207 and has been
> assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2009-0638.
>
> Vulnerability Scoring Details
> +----------------------------
>
> Cisco has provided scores for the vulnerability in this advisory based
> on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in
> this Security Advisory is done in accordance with CVSS version 2.0.
>
> CVSS is a standards-based scoring method that conveys vulnerability
> severity and helps determine urgency and priority of response.
>
> Cisco has provided a base and temporal score. Customers can then
> compute environmental scores to assist in determining the impact of  
> the
> vulnerability in individual networks.
>
> Cisco has provided a FAQ to answer additional questions regarding CVSS
> at:
>
> http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html
>
> Cisco has also provided a CVSS calculator to help compute the
> environmental impact for individual networks at:
>
> http://intellishield.cisco.com/security/alertmanager/cvss
>
>
> * NP 2 threads lock due to processing crafted ICMP message  
> (CSCsz97207)
>
> CVSS Base Score - 7.8
>    Access Vector -            Network
>    Access Complexity -        Low
>    Authentication -           None
>    Confidentiality Impact -   None
>    Integrity Impact -         None
>    Availability Impact -      Complete
>
> CVSS Temporal Score - 6.4
>    Exploitability -           Functional
>    Remediation Level -        Official-Fix
>    Report Confidence -        Confirmed
>
>
> Impact
> ======
>
> Successful exploitation of the vulnerability may cause the FWSM to
> stop forwarding traffic between interfaces (transit traffic), and stop
> processing traffic directed at the FWSM (management traffic). If the
> FWSM is configured for failover operation, the active FWSM may not  
> fail
> over to the standby FWSM.
>
> Software Versions and Fixes
> ===========================
>
> 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.
>
> Each row of the FWSM software table below describes a major FWSM
> software train and the earliest possible release within that train  
> that
> contains the fix (the "First Fixed Release") and the anticipated  
> date of
> availability (if not currently available) in the "First Fixed Release"
> column. A device running a release that is earlier than the release in
> a specific column (less than the First Fixed Release) is known to be
> vulnerable. The release should be upgraded at least to the indicated
> release or a later version (greater than or equal to the First Fixed
> Release label).
>
> +---------------------------------------+
> |   Major    |   First Fixed Release    |
> |  Release   |                          |
> |------------+--------------------------|
> | 2.x        | Vulnerable; migrate to   |
> |            | 3.x or 4.x               |
> |------------+--------------------------|
> | 3.1        | 3.1(16)                  |
> |------------+--------------------------|
> | 3.2        | 3.2(13)                  |
> |------------+--------------------------|
> | 4.0        | 4.0(6)                   |
> +---------------------------------------+
>
> Fixed FWSM software can be downloaded from the Software Center on
> cisco.com by visiting http://www.cisco.com/public/sw-center/ 
> index.shtml
> and navigating to "Security" > "Cisco Catalyst 6500 Series Firewall
> Services Module" > "Firewall Services Module (FWSM) Software".
>
> Workarounds
> ===========
>
> There are no workarounds for this vulnerability. Access control lists
> (ACLs) that are deployed on the FWSM itself to block through-the- 
> device
> or to-the-device ICMP messages are not effective to prevent this
> vulnerability. However, blocking unnecessary ICMP messages on  
> screening
> devices or on devices in the path to the FWSM will prevent the FWSM
> from triggering the vulnerability. For example, the following ACL,
> when deployed on a Cisco IOS device in front of the FWSM, will prevent
> crafted ICMP messages from reaching the FWSM, and thus protect the  
> FWSM
> from triggering the vulnerability:
>
>    access-list 101 permit icmp any any echo
>    access-list 101 permit icmp any any echo-reply
>    access-list 101 permit icmp any any traceroute
>    access-list 101 permit icmp any any packet-too-big
>    access-list 101 permit icmp any any time-exceeded
>    access-list 101 permit icmp any any host-unreachable
>    access-list 101 permit icmp any any unreachable
>    access-list 101 deny   icmp any any
>    access-list 101 permit ip any any
>
> This sample ACL is allowing certain ICMP messages that are vital for
> network troubleshooting and for proper operation of the network. It is
> safe to allow any other ICMP messages for which the Cisco IOS Software
> "access-list" command has named ICMP type keywords. ACLs like the one
> in the preceding example may also be deployed on non-Cisco IOS  
> devices,
> such as the Cisco PIX and ASA security appliances, although the ACL
> syntax on non-Cisco IOS devices may not support all the named ICMP  
> type
> keywords that the Cisco IOS ACL syntax supports. However, on non-Cisco
> IOS devices, it is safe to permit all ICMP messages for which there  
> are
> named ICMP type keywords in the ACL syntax.
>
> As mentioned in the Details section, if the FWSM has stopped  
> processing
> traffic due to this vulnerability, the FWSM will require a reload.
> Administrators can reload the FWSM by logging in to the supervisor
> of the Catalyst 6500 Series Switch or the Cisco 7600 Series router
> and issuing the "hw-module module <slot # for FWSM> reset" (Cisco
> IOS Software), or "set module power up|down <module #>" (Cisco CatOS
> Software) commands.
>
> Additional mitigations that can be deployed on Cisco devices within  
> the
> network are available in the Cisco Applied Mitigation Bulletin  
> companion
> document for this advisory, which is available at the following link:
>
> http://www.cisco.com/warp/public/707/cisco-amb-20090819-fwsm.shtml.
>
> Obtaining Fixed Software
> ========================
>
> Cisco has released free software updates that address this
> vulnerability. 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/en/US/docs/general/warranty/English/EU1KEN_.html,
> or as otherwise set forth at Cisco.com Downloads at
> http://www.cisco.com/public/sw-center/sw-usingswc.shtml.
>
> Do not contact psirt at cisco.com or security-alert at 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 agreements 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 do not hold a Cisco  
> service
> contract, and customers who purchase through third-party vendors but  
> are
> unsuccessful in obtaining fixed software through their point of sale
> should acquire 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 at cisco.com
>
> Customers should have their product serial number available and be
> prepared to give the URL of this notice as evidence of entitlement  
> to a
> free upgrade. Free upgrades for non-contract customers must be  
> requested
> through the TAC.
>
> Refer to
> http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html
> for additional TAC contact information, including 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 public announcements or malicious
> use of the vulnerability described in this advisory, but Cisco is  
> aware
> of customers that have encountered this vulnerability during normal
> network operation.
>
> This vulnerability was discovered during the handling of customer
> support cases.
>
> 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-20090819-fwsm.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 at cisco.com
>  * first-bulletins at lists.first.org
>  * bugtraq at securityfocus.com
>  * vulnwatch at vulnwatch.org
>  * cisco at spot.colorado.edu
>  * cisco-nsp at puck.nether.net
>  * full-disclosure at lists.grok.org.uk
>  * comp.dcom.sys.cisco at 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 1.0  | 2009-August-19  | Initial 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.
>
> +--------------------------------------------------------------------
> Copyright 2008-2009 Cisco Systems, Inc. All rights reserved.
> +--------------------------------------------------------------------
>
> Updated: Aug 19, 2009                             Document ID: 110460
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