__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Cisco IOS Multicast Virtual Private Network (MVPN) Data Leak [Cisco Security Advisory Document ID: 100374] April 10, 2008 15:00 GMT Number S-262 ______________________________________________________________________________ PROBLEM: A vulnerability in the Cisco implementation of Multicast Virtual Private Network (MVPN) is subject to exploitation that can allow a malicious user to create extra multicast states on the core routers or receive multicast traffic from other Multiprotocol Label Switching (MPLS) based Virtual Private Networks (VPN) by sending specially crafted messages. PLATFORM: Devices that run Cisco IOS and are configured for MVPN are affected. DAMAGE: Data leak. SOLUTION: Upgrade to the appropriate version. ______________________________________________________________________________ VULNERABILITY The risk is LOW. Successful exploitation of the vulnerability ASSESSMENT: can result in the creation of extra multicast states on the core routers or the leaking of multicast traffic from one MPLS VPN to another. ______________________________________________________________________________ CVSS 2 BASE SCORE: 7.5 TEMPORAL SCORE: 6.2 VECTOR: (AV:N/AC:L/Au:N/C:P/I:P/A:P/E:F/RL:OF/RC:C) ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/s-262.shtml ORIGINAL BULLETIN: http://www.cisco.com/en/US/products/products_security_ advisory09186a0080969868.shtml CVE: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name= CVE-2008-1156 ______________________________________________________________________________ [***** Start Cisco Security Advisory Document ID: 100374 *****] Cisco Security Advisory: Cisco IOS Multicast Virtual Private Network (MVPN) Data Leak Document ID: 100374 Advisory ID: cisco-sa-20080326-mvpn http://www.cisco.com/warp/public/707/cisco-sa-20080326-mvpn.shtml Revision 1.1 Last Updated 2008 March 29 0300 UTC (GMT) For Public Release 2008 March 26 1600 UTC (GMT) -------------------------------------------------------------------------------- Contents Summary Affected Products Details Vulnerability Scoring 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 A vulnerability in the Cisco implementation of Multicast Virtual Private Network (MVPN) is subject to exploitation that can allow a malicious user to create extra multicast states on the core routers or receive multicast traffic from other Multiprotocol Label Switching (MPLS) based Virtual Private Networks (VPN) by sending specially crafted messages. Cisco has released free software updates that address this vulnerability. Workarounds that mitigate this vulnerability are available. This advisory is posted at http://www.cisco.com/warp/public/707/cisco-sa-20080326-mvpn.shtml. Note: The March 26, 2008 publication includes five Security Advisories. The Advisories all affect Cisco IOS. Each Advisory lists the releases that correct the vulnerability described in the Advisory, and the Advisories also detail the releases that correct the vulnerabilities in all five Advisories. Please reference the following software table to find a release that fixes all published Security Advisories as of March 26th, 2008. March 26th bundled IOS Advisory Table http://www.cisco.com/warp/public/707/cisco-sa-20080326-bundle.shtml Individual publication links are listed below: Cisco IOS Virtual Private Dial-up Network Denial of Service Vulnerability http://www.cisco.com/warp/public/707/cisco-sa-20080326-pptp.shtml Multiple DLSw Denial of Service Vulnerabilities in Cisco IOS http://www.cisco.com/warp/public/707/cisco-sa-20080326-dlsw.shtml Cisco IOS User Datagram Protocol Delivery Issue For IPv4/IPv6 Dual-stack Routers http://www.cisco.com/warp/public/707/cisco-sa-20080326-IPv4IPv6.shtml Vulnerability in Cisco IOS with OSPF, MPLS VPN, and Supervisor 32, Supervisor 720, or Route Switch Processor 720 http://www.cisco.com/warp/public/707/cisco-sa-20080326-queue.shtml Cisco IOS Multicast Virtual Private Network (MVPN) Data Leak http://www.cisco.com/warp/public/707/cisco-sa-20080326-mvpn.shtml [Expand all sections] [Collapse all sections] Affected Products Vulnerable Products Devices that run Cisco IOS and are configured for MVPN are affected. An IOS device that is configured for MVPN has a line that is similar to this in the running configuration example: mdt default In order to determine the software that runs on a Cisco IOS product, log in to the device and issue the show version command to display the system banner. Cisco IOSŪ software identifies itself as "Internetwork Operating System Software" or simply "IOS." On the next line of output, the image name displays between parentheses, followed by "Version" and the Cisco IOS release name. Other Cisco devices do not have the show version command or give different output. The following example shows output from a device that runs an IOS image: Router>show version Cisco IOS Software, 7200 Software (C7200-IK9S-M), Version 12.3(14)T1, RELEASE SOFTWARE (fc1) Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2005 by Cisco Systems, Inc. Compiled Thu 31-Mar-05 08:04 by yiyan Additional information about Cisco IOS release naming is available at the following link: http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_white_ paper09186a008018305e.shtml. Products Confirmed Not Vulnerable No other Cisco products, including IOS XR software, are currently known to be affected by this vulnerability. Top of the section Close Section Details MVPN architecture introduces an additional set of protocols and procedures that help enable a service provider to support multicast traffic in an MPLS VPN. MVPN allows the transparent transport of IP multicast traffic across the MPLS VPN backbone of a provider and allows a service provider to offer multicast services to MPLS VPN customers. A vulnerability exists in the implementation of MVPN that allows an attacker to send specially crafted Multicast Distribution Tree (MDT) Data Join messages that can cause the creation of extra multicast states on the core routers. MDT Data Join messages can be sent in unicast or multicast. The vulnerability can also allow leaking multicast traffic from different MPLS VPNs. It is possible to receive multicast traffic from VPNs that are not connected to the same Provider Edge (PE) router. In order to successfully exploit this vulnerability, an attacker needs to know or guess the Border Gateway Protocol (BGP) peering IP address of a remote PE router and the address of the multicast group that is used in other MPLS VPNs. This vulnerability is documented in the Cisco Bug ID CSCsi01470 ( registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2008-1156. Top of the section Close Section Vulnerability Scoring Details Cisco has provided scores for the vulnerabilities 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 an 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 . CSCsi01470 - Crafted MDT Data Join TLV in VRF causes multicast state in core Calculate the environmental score of CSCsi01470 CVSS Base Score - 7.5 Access Vector Access Complexity Authentication Confidentiality Impact Integrity Impact Availability Impact Network Low None Partial Partial Partial CVSS Temporal Score - 6.2 Exploitability Remediation Level Report Confidence Functional Official-Fix Confirmed Top of the section Close Section Impact Successful exploitation of the vulnerability can result in the creation of extra multicast states on the core routers or the leaking of multicast traffic from one MPLS VPN to another. Top of the section Close Section 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 Cisco IOS software table (below) names a Cisco IOS release train. If a given release train is vulnerable, then the earliest possible releases that contain the fix (along with the anticipated date of availability for each, if applicable) are listed in the "First Fixed Release" column of the table. The "Recommended Release" column indicates the releases which have fixes for all the published vulnerabilities at the time of this Advisory. 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. Cisco recommends upgrading to a release equal to or later than the release in the "Recommended Releases" column of the table. Major Release Availability of Repaired Releases Affected 12.0-Based Releases First Fixed Release Recommended Release 12.0 Not Vulnerable 12.0DA Not Vulnerable 12.0DB Not Vulnerable 12.0DC Not Vulnerable 12.0S 12.0(32)S9 12.0(33)S 12.0SC Not Vulnerable 12.0SL Not Vulnerable 12.0SP Not Vulnerable 12.0ST Not Vulnerable 12.0SX Vulnerable; Contact TAC 12.0SY 12.0(32)SY4 12.0SZ 12.0(30)SZ4 12.0T Not Vulnerable 12.0W Not Vulnerable 12.0WC Not Vulnerable 12.0WT Not Vulnerable 12.0XA Not Vulnerable 12.0XB Not Vulnerable 12.0XC Not Vulnerable 12.0XD Not Vulnerable 12.0XE Not Vulnerable 12.0XF Not Vulnerable 12.0XG Not Vulnerable 12.0XH Not Vulnerable 12.0XI Not Vulnerable 12.0XJ Not Vulnerable 12.0XK Not Vulnerable 12.0XL Not Vulnerable 12.0XM Not Vulnerable 12.0XN Not Vulnerable 12.0XQ Not Vulnerable 12.0XR Not Vulnerable 12.0XS Not Vulnerable 12.0XV Not Vulnerable 12.0XW Not Vulnerable Affected 12.1-Based Releases First Fixed Release Recommended Release There are no affected 12.1 based releases Affected 12.2-Based Releases First Fixed Release Recommended Release 12.2 Not Vulnerable 12.2B Vulnerable; first fixed in 12.4 12.4(18a) 12.2BC Vulnerable; first fixed in 12.3BC 12.3(23)BC1 12.2BW Not Vulnerable 12.2BY Not Vulnerable 12.2BZ Vulnerable; first fixed in 12.3XI 12.2CX Vulnerable; first fixed in 12.3BC 12.3(23)BC1 12.2CY Not Vulnerable 12.2CZ Vulnerable; contact TAC 12.2DA Not Vulnerable 12.2DD Not Vulnerable 12.2DX Not Vulnerable 12.2EU Vulnerable; first fixed in 12.2SG 12.2(25)EWA13 12.2(31)SGA5 12.2(44)SG 12.2EW Vulnerable; first fixed in 12.2SG 12.2(25)EWA13 12.2(31)SGA5 12.2(44)SG 12.2EWA 12.2(25)EWA10 12.2(25)EWA11 12.2(25)EWA13 12.2EX 12.2(37)EX 12.2(40)EX1 12.2EY 12.2(37)EY 12.2EZ Vulnerable; first fixed in 12.2SEE 12.2FX Not Vulnerable 12.2FY Not Vulnerable 12.2FZ Vulnerable; first fixed in 12.2SE 12.2(44)SE1 12.2IXA Vulnerable; first fixed in 12.2IXD 12.2IXB Vulnerable; first fixed in 12.2IXD 12.2IXC Vulnerable; first fixed in 12.2IXD 12.2IXD 12.2(18)IXD1 12.2IXE Not Vulnerable 12.2JA Not Vulnerable 12.2JK Not Vulnerable 12.2MB Not Vulnerable 12.2MC 12.2(15)MC2h 12.2(15)MC2k 12.2S 12.2(14)S18 12.2(18)S13 12.2(20)S14 12.2(25)S13 12.2(25)S15 12.2SB 12.2(28)SB7 12.2(31)SB5 12.2(33)SB; Available on 31-MAR-2008 12.2(31)SB11 12.2SBC Vulnerable; first fixed in 12.2SB; Available on 31-MAR-2008 12.2(31)SB11 12.2SCA Not Vulnerable 12.2SE 12.2(35)SE4 12.2(37)SE 12.2(44)SE1 12.2SEA Vulnerable; first fixed in 12.2SEE 12.2SEB Vulnerable; first fixed in 12.2SEE 12.2SEC Vulnerable; first fixed in 12.2SEE 12.2SED Vulnerable; first fixed in 12.2SEE 12.2SEE 12.2(25)SEE4 12.2SEF Not Vulnerable 12.2SEG 12.2(25)SEG3 12.2(25)SEG4 12.2SG 12.2(25)SG2 12.2(31)SG2 12.2(37)SG1 12.2(40)SG 12.2(44)SG 12.2SGA 12.2(31)SGA2 12.2(31)SGA3 12.2(31)SGA6; Available on 07-APR-2008 12.2(31)SGA5 12.2SL Not Vulnerable 12.2SM 12.2(29)SM2 12.2SO Vulnerable; migrate to any release in 12.2SVA 12.2(29)SVD 12.2SRA 12.2(33)SRA4 12.2(33)SRA7 12.2SRB 12.2(33)SRB1 12.2(33)SRB3; Available on 14-APR-08 12.2SRC Not Vulnerable 12.2SU Vulnerable; first fixed in 12.4 12.4(18a) 12.2SV 12.2(29b)SV 12.2(29b)SV 12.2SVA Not Vulnerable 12.2SVC Not Vulnerable 12.2SVD Not Vulnerable 12.2SW 12.2(25)SW11 12.2SX Vulnerable; first fixed in 12.2SXF 12.2(18)SXF13 12.2SXA Vulnerable; first fixed in 12.2SXF 12.2(18)SXF13 12.2SXB Vulnerable; first fixed in 12.2SXF 12.2(18)SXF13 12.2SXD Vulnerable; first fixed in 12.2SXF 12.2(18)SXF13 12.2SXE Vulnerable; first fixed in 12.2SXF 12.2(18)SXF13 12.2SXF 12.2(18)SXF10 12.2(18)SXF10a 12.2(18)SXF12a 12.2(18)SXF13 12.2SXH Not Vulnerable 12.2SY Vulnerable; first fixed in 12.2SXF 12.2(18)SXF13 12.2SZ Vulnerable; first fixed in 12.2S 12.2(25)S15 12.2(31)SB11 12.2(33)SRC 12.2T Vulnerable; first fixed in 12.3 12.3(26) 12.2TPC Not Vulnerable 12.2UZ Vulnerable; first fixed in 12.2SB; Available on 31-MAR-2008 12.2(31)SB11 12.2XA Not Vulnerable 12.2XB Not Vulnerable 12.2XC Not Vulnerable 12.2XD Not Vulnerable 12.2XE Not Vulnerable 12.2XF Not Vulnerable 12.2XG Not Vulnerable 12.2XH Not Vulnerable 12.2XI Not Vulnerable 12.2XJ Not Vulnerable 12.2XK Not Vulnerable 12.2XL Not Vulnerable 12.2XM Not Vulnerable 12.2XN 12.2(33)XN1 12.3(26) 12.2XO Not Vulnerable 12.2XQ Not Vulnerable 12.2XR Not Vulnerable 12.2XS Not Vulnerable 12.2XT Not Vulnerable 12.2XU Not Vulnerable 12.2XV Not Vulnerable 12.2XW Not Vulnerable 12.2YA Not Vulnerable 12.2YB Not Vulnerable 12.2YC Not Vulnerable 12.2YD Not Vulnerable 12.2YE Not Vulnerable 12.2YF Not Vulnerable 12.2YG Not Vulnerable 12.2YH Vulnerable; first fixed in 12.3 12.3(26) 12.2YJ Vulnerable; first fixed in 12.3 12.3(26) 12.2YK Not Vulnerable 12.2YL Vulnerable; first fixed in 12.4 12.4(18a) 12.2YM Vulnerable; first fixed in 12.4 12.4(18a) 12.2YN Vulnerable; first fixed in 12.4 12.4(18a) 12.2YO Not Vulnerable 12.2YP Not Vulnerable 12.2YQ Vulnerable; first fixed in 12.4 12.4(18a) 12.2YR Vulnerable; first fixed in 12.4 12.4(18a) 12.2YS Not Vulnerable 12.2YT Vulnerable; first fixed in 12.3 12.3(26) 12.2YU Vulnerable; first fixed in 12.4 12.4(18a) 12.2YV Vulnerable; first fixed in 12.4 12.4(18a) 12.2YW Not Vulnerable 12.2YX Vulnerable; first fixed in 12.4 12.4(18a) 12.2YY Not Vulnerable 12.2YZ Vulnerable; first fixed in 12.2S 12.2(25)S15 12.2(31)SB11 12.2(33)SRC 12.2ZA Vulnerable; first fixed in 12.2SXF 12.2(18)SXF13 12.2ZB Not Vulnerable 12.2ZC Vulnerable; first fixed in 12.4 12.4(18a) 12.2ZD Vulnerable; contact TAC 12.2ZE Vulnerable; first fixed in 12.3 12.3(26) 12.2ZF Vulnerable; first fixed in 12.4 12.4(18a) 12.2ZG Vulnerable; first fixed in 12.3YG 12.4(15)T4 12.4(18a) 12.2ZH 12.2(13)ZH9 12.2(13)ZH11 12.2ZJ Vulnerable; first fixed in 12.4 12.4(18a) 12.2ZL Vulnerable; first fixed in 12.4 12.4(15)T4 12.4(18a) 12.2ZP Vulnerable; first fixed in 12.4 12.4(18a) 12.2ZU Vulnerable; migrate to any release in 12.2SXH 12.2(33)SXH2 12.2ZY 12.2(18)ZY1 12.2(18)ZY2 Affected 12.3-Based Releases First Fixed Release Recommended Release 12.3 12.3(17c) 12.3(18a) 12.3(19a) 12.3(20a) 12.3(21b) 12.3(22a) 12.3(23) 12.3(26) 12.3B Vulnerable; first fixed in 12.4 12.4(18a) 12.3BC 12.3(17b)BC8 12.3(21a)BC2 12.3(23)BC 12.3(23)BC1 12.3BW Vulnerable; first fixed in 12.4 12.4(18a) 12.3EU Not Vulnerable 12.3JA Not Vulnerable 12.3JEA Not Vulnerable 12.3JEB Not Vulnerable 12.3JEC Not Vulnerable 12.3JK Releases prior to 12.3(8)JK1 are vulnerable, release 12.3(8)JK1 and later are not vulnerable; 12.3(8)JK1 12.3JL Not Vulnerable 12.3JX Not Vulnerable 12.3T Vulnerable; first fixed in 12.4 12.4(18a) 12.3TPC 12.3(4)TPC11b 12.3VA Vulnerable; contact TAC 12.3XA 12.3(2)XA6 12.3(2)XA7; Available on 31-MAR-08 12.3XB Vulnerable; first fixed in 12.4 12.4(18a) 12.3XC 12.3(2)XC5 12.4(15)T4 12.4(18a) 12.3XD Vulnerable; first fixed in 12.4 12.4(18a) 12.3XE 12.3(2)XE5 12.4(15)T4 12.4(18a) 12.3XF Vulnerable; first fixed in 12.4 12.4(18a) 12.3XG Vulnerable; first fixed in 12.3YG 12.4(15)T4 12.4(18a) 12.3XH Vulnerable; first fixed in 12.4 12.4(18a) 12.3XI 12.3(7)XI10a 12.3XJ Vulnerable; first fixed in 12.3YX 12.3(14)YX11 12.4(15)T4 12.3XK Vulnerable; first fixed in 12.4 12.4(18a) 12.3XQ Vulnerable; first fixed in 12.4 12.4(18a) 12.3XR 12.3(7)XR7 12.3(7)XR8; Available on 31-MAR-08 12.3XS Vulnerable; first fixed in 12.4 12.4(18a) 12.3XU Vulnerable; first fixed in 12.4T 12.4(15)T4 12.3XW Vulnerable; first fixed in 12.3YX 12.3(14)YX11 12.4(15)T4 12.3XY Vulnerable; first fixed in 12.4 12.4(18a) 12.3YA Vulnerable; first fixed in 12.4 12.4(15)T4 12.4(18a) 12.3YD Vulnerable; first fixed in 12.4T 12.4(15)T4 12.3YF Vulnerable; first fixed in 12.3YX 12.3(14)YX11 12.4(15)T4 12.3YG 12.3(8)YG6 12.4(15)T4 12.3YH Vulnerable; first fixed in 12.4T 12.4(15)T4 12.3YI Vulnerable; first fixed in 12.4T 12.4(15)T4 12.3YJ Vulnerable; first fixed in 12.4T 12.4(15)T4 12.3YK 12.3(11)YK3 12.4(15)T4 12.3YM 12.3(14)YM10 12.3(14)YM12 12.3YQ Vulnerable; first fixed in 12.4T 12.4(15)T4 12.3YS 12.3(11)YS2 12.4(15)T4 12.3YT Vulnerable; first fixed in 12.4T 12.4(15)T4 12.3YU Vulnerable; first fixed in 12.4XB 12.3YX 12.3(14)YX9 12.3(14)YX11 12.3YZ 12.3(11)YZ2 Affected 12.4-Based Releases First Fixed Release Recommended Release 12.4 12.4(10c) 12.4(12b) 12.4(13c) 12.4(16) 12.4(3h) 12.4(5c) 12.4(7f) 12.4(8d) 12.4(18a) 12.4JA Not Vulnerable 12.4JK Not Vulnerable 12.4JMA Not Vulnerable 12.4JMB Not Vulnerable 12.4JMC Not Vulnerable 12.4JX Not Vulnerable 12.4MD 12.4(11)MD1 12.4(15)MD; Available on 09-MAY-08 12.4MR 12.4(12)MR2 12.4(16)MR2 12.4SW 12.4(11)SW3 12.4(15)SW 12.4T 12.4(11)T3 12.4(15)T 12.4(2)T6 12.4(4)T8 12.4(6)T8 12.4(9)T4 12.4(15)T4 12.4XA Vulnerable; first fixed in 12.4T 12.4(15)T4 12.4XB 12.4(2)XB6 12.4XC 12.4(4)XC7 12.4XD 12.4(4)XD8 12.4(4)XD10 12.4XE 12.4(6)XE2 12.4(15)T4 12.4XF Vulnerable; first fixed in 12.4T 12.4(15)T4 12.4XG 12.4(9)XG2 12.4(9)XG2 12.4XJ 12.4(11)XJ4 12.4(15)T4 12.4XK Vulnerable; first fixed in 12.4T 12.4(15)T4 12.4XL Not Vulnerable 12.4XM Not Vulnerable 12.4XN Not Vulnerable 12.4XT 12.4(6)XT1 12.4(6)XT2 12.4XV Not Vulnerable 12.4XW Not Vulnerable 12.4XY Not Vulnerable Top of the section Close Section Workarounds The workaround for this vulnerability consists of filtering MDT Data Join packets on the PE device. The workarounds need to be applied on all Virtual Routing and Forwarding (VRF) interfaces of all PE routers. Otherwise, attackers can target remote PE routers and can still exploit this vulnerability. Even if only one PE router in the network runs an unfixed version of IOS code, it is vulnerable to packets that come from systems that are connected to remote PE routers. In such a case, workarounds need to be deployed on all PE routers to successfully mitigate this vulnerability. The mdt data or mdt data threshold list commands do not mitigate this vulnerability. Filtering Packets to UDP Port 3232 MDT Data Join messages are sent to UDP port 3232. Creating an access-list that filters destination UDP port 3232 and applying it on the VRF interface of the PE router mitigates this vulnerability. Such an access-list looks like this: access-list 100 deny udp any any eq 3232 access-list 100 permit ip any any interface Serial 0/0 ip vrf forwarding ... ip access-group 100 in Note that this access-list can also filter legitimate traffic that is destined to UDP port 3232. In such a case, the access-list can be modified to be more specific by providing individual BGP peer IP addresses. This is explained in the section that follows. Filtering BGP Peer IP Addresses on the VRF Interface In order to successfully exploit this vulnerability, an attacker needs to send MDT Data Join messages by spoofing the packets from the IP address of one of the existing iBGP peers. Because MDT Data Join messages are only used between PE routers, the packets from CE devices can safely be filtered. Creating an access-list that filters iBGP peer IP addresses as source addresses and applying it on the VRF interface of the PE router mitigates this vulnerability. The access-list needs to filter all iBGP peer IP addresses. Such an access-list looks like this example: access-list 100 deny udp host any eq 3232 access-list 100 deny udp host any eq 3232 ... access-list 100 deny udp host any eq 3232 access-list 100 permit ip any any interface Serial 0/0 ip vrf forwarding ... ip access-group 100 in Additional mitigation techniques that can be deployed on Cisco devices within the network are available in the Cisco Applied Mitigation Bulletin companion document for this advisory: http://www.cisco.com/warp/public/707/cisco-amb-20080326-mvpn.shtml Top of the section Close Section 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/products/prod_warranties_item09186a008088e31f.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@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 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@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/warp/public/687/Directory/DirTAC.shtml for additional TAC contact information, including localized telephone numbers, and instructions and e-mail addresses for use in various languages. Top of the section Close Section Exploitation and Public Announcements The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory. This vulnerability was reported to Cisco by Thomas Morin. Top of the section Close Section 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. Top of the section Close Section Distribution This advisory is posted on Cisco's worldwide website at : http://www.cisco.com/warp/public/707/cisco-sa-20080326-mvpn.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. Top of the section Close Section Revision History Revision 1.1 2008-March-29 Updated Software Table for 12.0S, 12.0SY, 12.0SX and 12.0SZ due to new information on advisory ID cisco-sa-20080326-IPv4IPv6, the March 26th advisory on IPv4IPv6 Dual Stack Routers. Revision 1.0 2008-March-26 Initial public release. [***** End Cisco Security Advisory Document ID: 100374 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Cisco for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC) S-213: Nukedit 'email' Parameter Vulnerability S-214: SurgeMail and WebMail 'Page' Command Vulnerability S-215: Symantec Backup Exec Scheduler ActiveX Control Multiple Vulnerabilities S-216: Juniper Networks Secure Access 2000 'rdremediate.cgi' Vulnerability S-217: Drupal Multiple HTML Vulnerabilities S-218: gd Security Update S-219: Juniper Networks Secure Access 2000 Web Root Path Vulnerability S-220: PHP-Nuke My_eGallery Module 'gid' Parameter Vulnerability S-221: Learn2 STRunner ActiveX Control Vulnerabilities S-222: Evolution Security Update