-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Cisco Security Advisory: SIP Packet Reloads IOS Devices Not Configured for SIP Advisory ID: cisco-sa-20070131-sip http://www.cisco.com/warp/public/707/cisco-sa-20070131-sip.shtml Revision 1.0 For Public Release 2007 Jan 31 0900 UTC (GMT) - --------------------------------------------------------------------- Summary ======= Cisco devices running IOS which support voice and are not configured for Session Initiated Protocol (SIP) are vulnerable to a crash under yet to be determined conditions, but isolated to traffic destined to Port 5060. SIP is enabled by default on all Advanced images which support voice and do not contain the fix for CSCsb25337. There are no reports of this vulnerability on the devices which are properly configured for SIP processing. Workarounds exist to mitigate the effects of this problem. This advisory is posted at http://www.cisco.com/warp/public/707/cisco-sa-20070131-sip.shtml Affected Products ================= IOS releases that include voice support after 12.3(14)T, 12.3(8)YC1, 12.3(8)YG and all of 12.4 are affected. Please see the fixed software table for a complete list of fixed and vulnerable trains. To determine if your device has SIP enabled, enter the commands 'show ip sockets' and 'show tcp brief all'. Below is an example of a router running code without the fix, and without the workaround enabled. The router in this example is vulnerable to this issue. IOS image in example: 7200-p-mz.124-3.bin Router#show ip sockets Proto Remote Port Local Port In Out Stat TTY OutputIF 17 0.0.0.0 0 --any-- 5060 0 0 211 0 17 0.0.0.0 0 192.168.100.2 67 0 0 2211 0 17 0.0.0.0 0 192.168.100.2 2517 0 0 11 0 The first line with UDP Port 5060 shows that UDP SIP is enabled. Router#show tcp brief all TCB Local Address Foreign Address (state) 2051E680 *.5060 *.* LISTEN 2051E680 *.5060 *.* LISTEN The above lines with *.5060 show that TCP SIP is enabled. Vulnerable Products +------------------ The following is a list of products that support voice and could be affected by this vulnerability. * 815 * 871 * 876 * 877 * 878 * 1701 * 1711 * 1712 * 1721 * 1751 * 1751-V * 1760 * 1801 * 1802 * 1803 * 1811 * 1812 * 1841 * 2610XM-2611XM * 2620XM-2621XM * 2650XM-2651XM * 2691 * 2801 * 2811 * 2821 * 2851 * 3220 * 3250 * 3270 * 3725 * 3745 * 3825 * 3845 * 7200 * 7200-NPE-G2 * 7301 Products Confirmed Not Vulnerable +-------------------------------- Devices which do not support voice are not affected by this issue. Devices which are properly configured for SIP processing are not affected by this issue. We have no reports of this vunerability on devices that are configured for SIP processing. We also have no reports of affected IOS-XR devices, CatOS devices, or any device which does not run IOS, but can not conclusively rule them out without further testing. This advisory will be updated with more information as it becomes available. Below is an example of a router not vulnerable to this issue. The router in this example is running the fixed release c7200-js-mz.124-5b.bin. Router#show tcp brief all Router#show ip sockets Proto Remote Port Local Port In Out Stat TTY OutputIF 17 0.0.0.0 0 192.168.100.2 67 0 0 2211 0 No lines with UDP Port 5060 are shown and UDP SIP is not enabled. In this example UDP port 67 is used by DHCP is not related to this vulnerability. Details ======= SIP is a protocol designed for use in IP phone networks, and is widely used for Voice over Internet Protocol (VOIP) communications worldwide. Cisco devices running an affected image which supports voice services automatically enable SIP, which opens a listening port on UDP port 5060. TCP port 5060 is also opened, but does not appear to be related to the IOS crash detailed in this advisory. CSCsb25337 turns off the listening ports TCP and UDP 5060, and there have been no reports of this vulnerability in any images with this fix integrated. Impact ====== Successful exploitation of the vulnerability may result in a reload of the device. The issue may be repeatedly exploited, leading to an extended Denial Of Service (DOS) condition. Software Version 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 Cisco IOS software table (below) describes a release train and the platforms or products for which it is intended. If a given release train is vulnerable, then the earliest possible releases that contain the fix (the "First Fixed Release") and the anticipated date of availability for each are listed in the "Rebuild" and "Maintenance" columns. A device running a release in the given train 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. For more information on the terms "Rebuild" and "Maintenance," consult the following URL: http://www.cisco.com/warp/public/620/1.html +---------------------------------------+ | Major | Availability of Repaired | | Release | Releases | |------------+--------------------------| | Affected | | | | 12.0-Based | Rebuild | Maintenance | | Release | | | |------------+--------------------------| | 12.0 | All 12.0 releases are | | | not vulnerable | |------------+--------------------------| | Affected | | | | 12.1-Based | Rebuild | Maintenance | | Release | | | |------------+--------------------------| | 12.1 | All 12.1 releases are | | | not vulnerable | |------------+--------------------------| | Affected | | | | 12.2-Based | Rebuild | Maintenance | | Release | | | |------------+--------------------------| | 12.2 | All 12.2 releases are | | | not vulnerable | |------------+--------------------------| | Affected | | | | 12.3-Based | Rebuild | Maintenance | | Release | | | |------------+--------------------------| | 12.3 | Not vulnerable | |------------+--------------------------| | 12.3B | Not vulnerable | |------------+--------------------------| | 12.3BC | Not vulnerable | |------------+--------------------------| | 12.3BW | Not vulnerable | |------------+--------------------------| | 12.3JA | Not vulnerable | |------------+--------------------------| | 12.3JEA | Not vulnerable | |------------+--------------------------| | 12.3JEB | Not vulnerable | |------------+--------------------------| | 12.3JK | Not vulnerable | |------------+--------------------------| | 12.3JX | Not vulnerable | |------------+--------------------------| | | Only 12.3(14)T releases | | | are vulnerable; migrate | | 12.3T | to 12.4(8) or later. All | | | other 12.3T releases are | | | not vulnerable. | |------------+--------------------------| | 12.3TPC | Not vulnerable | |------------+--------------------------| | 12.3XA | Not vulnerable | |------------+--------------------------| | 12.3XB | Not vulnerable | |------------+--------------------------| | 12.3XC | Not vulnerable | |------------+--------------------------| | 12.3XD | Not vulnerable | |------------+--------------------------| | 12.3XE | Not vulnerable | |------------+--------------------------| | 12.3XF | Not vulnerable | |------------+--------------------------| | 12.3XG | Not vulnerable | |------------+--------------------------| | 12.3XH | Not vulnerable | |------------+--------------------------| | 12.3XI | Not vulnerable | |------------+--------------------------| | 12.3XJ | Not vulnerable | |------------+--------------------------| | 12.3XK | Not vulnerable | |------------+--------------------------| | 12.3XQ | Not vulnerable | |------------+--------------------------| | 12.3XR | Not vulnerable | |------------+--------------------------| | 12.3XS | Not vulnerable | |------------+--------------------------| | 12.3XU | Not vulnerable | |------------+--------------------------| | 12.3XW | Not vulnerable | |------------+--------------------------| | 12.3XX | Not vulnerable | |------------+--------------------------| | 12.3XY | Not vulnerable | |------------+--------------------------| | 12.3YA | Not vulnerable | |------------+--------------------------| | 12.3YD | Not vulnerable | |------------+--------------------------| | 12.3YF | Not vulnerable | |------------+--------------------------| | 12.3YG | 12.3(8)YG5 | | |------------+--------------------------| | 12.3YH | Not vulnerable | |------------+--------------------------| | 12.3YI | Not vulnerable | |------------+--------------------------| | 12.3YJ | Not vulnerable | |------------+--------------------------| | 12.3YK | Vulnerable; migrate to | | | 12.4(4)T3 or later | |------------+--------------------------| | 12.3YM | 12.3(14) | | | | YM8 | | |------------+--------------------------| | 12.3YQ | Vulnerable; migrate to | | | 12.4(6)T1 or later | |------------+--------------------------| | 12.3YS | Not vulnerable | |------------+--------------------------| | 12.3YT | Vulnerable; migrate to | | | 12.4(4)T3 or later | |------------+--------------------------| | 12.3YU | Vulnerable; migrate to | | | 12.4(2)XB2 or later | |------------+--------------------------| | 12.3YX | 12.3(14) | | | | YX2 | | |------------+--------------------------| | 12.3YZ | Not vulnerable | |------------+--------------------------| | Affected | | | | 12.4-Based | Rebuild | Maintenance | | Release | | | |------------+------------+-------------| | | 12.4(3d) | | | |------------+-------------| | 12.4 | 12.4(5b) | | | |------------+-------------| | | 12.4(7a) | 12.4(8) | |------------+------------+-------------| | 12.4MR | | 12.4(6)MR | |------------+--------------------------| | 12.4SW | All 12.4SW releases are | | | fixed | |------------+--------------------------| | | 12.4(2)T5 | | | |------------+-------------| | 12.4T | 12.4(4)T3 | | | |------------+-------------| | | 12.4(6)T1 | 12.4(9)T | |------------+--------------------------| | 12.4XA | Vulnerable; migrate to | | | 12.4(6)T1 or later | |------------+--------------------------| | 12.4XB | 12.4(4)XB2 | | |------------+--------------------------| | 12.4XC | Vulnerable; contact TAC | |------------+--------------------------| | 12.4XD | 12.4(4)XD2 | | |------------+--------------------------| | 12.4XE | All 12.4XE releases are | | | fixed | |------------+--------------------------| | 12.4XG | All 12.4XG releases are | | | fixed | |------------+--------------------------| | 12.4XJ | All 12.4XJ releases are | | | fixed | |------------+--------------------------| | 12.4XP | All 12.4XP releases are | | | fixed | |------------+--------------------------| | 12.4XT | All 12.4XT releases are | | | fixed | +---------------------------------------+ Workarounds =========== Additional mitigations that can be deployed on Cisco devices within the network are available in the Cisco Applied Intelligence companion document for this advisory: http://www.cisco.com/warp/public/707/cisco-air-20070131-sip.shtml Turn off SIP processing +----------------------- Since this vulnerability is reported only in routers not configured for SIP, the simplest and most effective workaround is to turn SIP processing off. Enter configuration commands, one per line. End with CNTL/Z. Router(config)#sip-ua Router(config-sip-ua)#no transport udp Router(config-sip-ua)#no transport tcp Router(config-sip-ua)#end Control Plane Policing +--------------------- Cisco IOS software releases 12.0S, 12.2SX, 12.2S, 12.3T, 12.4, and 12.4T support the Control Plane Policing (CoPP) feature. CoPP may be configured on a device to protect the management and control planes to minimize the risk and effectiveness of direct infrastructure attacks by explicitly permitting only authorized traffic sent to infrastructure device in accordance with existing security policies and configurations. The following example can be adapted to your network. !-- Permit all TCP and UDP SIP traffic sent to all IP addresses !-- configured on all interfaces of the affected device so that it !-- will be policed and dropped by the CoPP feature access-list 100 permit tcp any any eq 5060 access-list 100 permit udp any any eq 5060 !-- Permit (Police or Drop)/Deny (Allow) all other Layer3 and Layer4 !-- traffic in accordance with existing security policies and !-- configurations for traffic that is authorized to be sent !-- to infrastructure devices ! !-- Create a Class-Map for traffic to be policed by !-- the CoPP feature class-map match-all drop-sip-class match access-group 100 !-- Create a Policy-Map that will be applied to the !-- Control-Plane of the device policy-map drop-sip-traffic class drop-sip-class drop !-- Apply the Policy-Map to the Control-Plane of the !-- device control-plane service-policy input drop-sip-traffic Note: In the above CoPP example, the access control list entries (ACEs) which match the potential exploit packets with the "permit" action result in these packets being discarded by the policy-map "drop" function, while packets that match the "deny" action (not shown) are not affected by the policy-map drop function. Additional information on the configuration and use of the CoPP feature can be found at http://www.cisco.com/en/US/products/ps6642/products_white_paper0900aecd804fa... and http://www.cisco.com/en/US/products/sw/iosswrel/ps1838/products_feature_guid.... Obtaining Fixed Software ======================== Cisco will make free software available to address this vulnerability for affected customers. This advisory will be updated as fixed software becomes available. 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 ===================================== This issue was first reported to Cisco by a customer. Cisco PSIRT is seeing randomly generated traffic which may be unintentionally causing this issue to manifest. Status of this Notice: INTERIM ============================== 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. CISCO EXPECTS TO UPDATE THIS DOCUMENT AS NEW INFORMATION BECOMES AVAILABLE. 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-20070131-sip.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 | 2007-January-31 | 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.h.... This includes instructions for press inquiries regarding Cisco security notices. All Cisco security advisories are available at http://www.cisco.com/go/psirt. - --------------------------------------------------------------------- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (Darwin) iD8DBQFFwGMG8NUAbBmDaxQRAlTmAKCRiz8v9q0ooRzpmx89W6HhITrUVwCZARsf mIdw8K1qQSI6UXkaxlUsXS8= =pSPg -----END PGP SIGNATURE-----