__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Multiple DLSw Denial of Service Vulnerabilities [Cisco Security Advisory Document ID: 99758] March 27, 2008 19:00 GMT Number S-241 [REVISED 2 Apr 2008] [REVISED 28 Apr 2008] ______________________________________________________________________________ PROBLEM: Cisco IOS contains multiple vulnerabilities in the Data-link Switching (DLSw) feature that may result in a reload or memory leaks when processing specially crafted UDP or IP Protocol 91 packets. PLATFORM: All Cisco products that run any version of affected Cisco IOS software configured for DLSw. DAMAGE: DoS. SOLUTION: Upgrade to the appropriate version. ______________________________________________________________________________ VULNERABILITY The risk is LOW. Successful exploitation of these ASSESSMENT: vulnerabilities may result in the reload of the device or memory leaks, leading to a DoS condition. ______________________________________________________________________________ CVSS 2 BASE SCORE: 7.8 TEMPORAL SCORE: 6.4 VECTOR: (AV:N/AC:L/Au:N/C:N/I:N/A:C/E:F/RL:OF/RC:C) ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/s-241.shtml ORIGINAL BULLETIN: http://www.cisco.com/en/US/products/products_security_ advisory09186a0080969866.shtml CVE: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name= CVE-2008-1152 ______________________________________________________________________________ REVISION HISTORY: 04/02/2008 - revised S-241 to reflect changed Cisco has made in Cisco Security Advisory Document ID: 99758 where they replaced IOS First Fixed Table with correct table -- data visible between 3/28 and 3/31 was incorrect; and 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. 04/28/2008 - revised S-241 to reflect changed Cisco has made in Cisco Security Advisory Document ID: 99768 where they added the specific link for IOS Software Modularity patch and updated the link to the CVSS score of CSCsk73104. [***** Start Cisco Security Advisory Document ID: 99758 *****] Cisco Security Advisory: Multiple DLSw Denial of Service Vulnerabilities in Cisco IOS Document ID: 99758 Advisory ID: cisco-sa-20080326-dlsw http://www.cisco.com/warp/public/707/cisco-sa-20080326-dlsw.shtml Revision 1.4 Last Updated 2008 April 25 2230 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 Cisco IOS contains multiple vulnerabilities in the Data-link Switching (DLSw) feature that may result in a reload or memory leaks when processing specially crafted UDP or IP Protocol 91 packets. Cisco has released free software updates that address these vulnerabilities. Workarounds are available to mitigate the effects of these vulnerabilities. This advisory is posted at http://www.cisco.com/warp/public/707/cisco-sa-20080326-dlsw.shtml. Note: The March 26, 2008 publication includes five Security Advisories. The Advisories all affect Cisco's Internetwork Operating System (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 which 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 This security advisory applies to all Cisco products that run any version of affected Cisco IOS software configured for DLSw. Systems that contain the DLSw feature, but do not have it enabled, are not affected. Routers enabled for DLSw contain a line in the configuration defining a local DLSw peer. This configuration can be observed by issuing the command show running-config. Systems configured for DLSw contain lines similar to the following: dlsw local-peer or dlsw local-peer peer-id Any version of Cisco IOS prior to the versions which are listed in the Software Versions and Fixes section below is vulnerable. To determine the version of Cisco IOS software running on a Cisco product, log in to the device and issue the show version command to display the system banner. Cisco IOS Software will identify itself as "Internetwork Operating System Software" or simply "IOS". On the next line of output, the image name will be displayed between parentheses, followed by "Version" and the IOS release name. Other Cisco devices will not have the show version command or will give different output. The following example identifies a Cisco product running Cisco IOS Software Release 12.3(6) with an installed image name of C3640-IS-M: Cisco Internetwork Operating System Software IOS (tm) 3600 Software (C3640-IS-M), Version 12.3(6), RELEASE SOFTWARE (fc3) The next example shows a product running Cisco IOS Software Release 12.3(11)T3 with an image name of C3845-ADVIPSERVICESK9-M: Cisco IOS Software, 3800 Software (C3845-ADVIPSERVICESK9-M), Version 12.3(11)T3, RELEASE SOFTWARE (fc4) Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2005 by Cisco Systems, Inc.Additional information about Cisco IOS release naming can be found at http://www.cisco.com/warp/public/620/1.html. Products Confirmed Not Vulnerable Cisco IOS devices that are not configured for DLSw are not vulnerable. No other Cisco products are currently known to be affected by these vulnerabilities. Top of the section Close Section Details Data-link switching (DLSw) provides a means of transporting IBM Systems Network Architecture (SNA) and network basic input/output system (NetBIOS) traffic over an IP network. Cisco implementation of DLSw also uses UDP port 2067 and IP Protocol 91 for Fast Sequenced Transport (FST). Multiple vulnerabilities exists in Cisco IOS when processing UDP and IP protocol 91 packets. These vulnerabilities do not affect TCP packet processing. A successful exploitation may result in a reload of the system or a memory leak on the device, leading to a denial of service (DoS) condition. Cisco IOS devices configured for DLSw with dlsw local-peer automatically listen for IP protocol 91 packets. A Cisco IOS device that is configured for DLSw with the dlsw local-peer peer-id command listen for IP protocol 91 packets and UDP port 2067. Cisco IOS devices listen to IP protocol 91 packets when DLSw is configured. However, it is only used if DLSw is configured for Fast Sequenced Transport (FST). A DLSw FST peer configuration will contain the following line: dlsw remote-peer 0 fst It is possible to disable UDP processing in DLSw with the dlsw udp-disable command. However, disabling UDP only prevents the sending of UDP packets, it does not prevent the device from receiving and processing incoming UDP packets. These vulnerabilities are documented in Cisco Bug ID CSCsk73104 ( registered customers only) and have been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2008-1152. 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 . CSCsk73104 - Handling of malformed packets by DLSW Calculate the environmental score of CSCsk73104 CVSS Base Score - 7.8 Access Vector Access Complexity Authentication Confidentiality Impact Integrity Impact Availability Impact Network Low None None None Complete CVSS Temporal Score - 6.4 Exploitability Remediation Level Report Confidence Functional Official-Fix Confirmed Top of the section Close Section Impact Successful exploitation of these vulnerabilities may result in the reload of the device or memory leaks, leading to a DoS condition. 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 Vulnerable; first fixed in 12.3 12.3(26) 12.0DA Releases prior to 12.0(8)DA3 are vulnerable, release 12.0(8)DA3 and later are not vulnerable; migrate to any release in 12.2DA 12.0DB Releases prior to 12.0(7)DB are vulnerable, release 12.0(7)DB and later are not vulnerable; first fixed in 12.4 12.4(18a) 12.0DC Releases prior to 12.0(7)DC are vulnerable, release 12.0(7)DC and later are not vulnerable; first fixed in 12.4 12.4(18a) 12.0S Releases prior to 12.0(17)S5 are vulnerable, release 12.0(17)S5 and later are not vulnerable; 12.0SC Not Vulnerable 12.0SL Not Vulnerable 12.0SP Not Vulnerable 12.0ST Not Vulnerable 12.0SX Not Vulnerable 12.0SY Not Vulnerable 12.0SZ Not Vulnerable 12.0T Vulnerable; first fixed in 12.3 12.3(26) 12.0W Vulnerable; contact TAC 12.0(3c)W5(8) 12.0WC Vulnerable; contact TAC 12.0WT Not Vulnerable 12.0XA Vulnerable; first fixed in 12.3 12.3(26) 12.0XB Not Vulnerable 12.0XC Releases prior to 12.0(2)XC2 are vulnerable, release 12.0(2)XC2 and later are not vulnerable; first fixed in 12.3 12.3(26) 12.0XD Vulnerable; first fixed in 12.3 12.3(26) 12.0XE Vulnerable; first fixed in 12.1E 12.0XF Not Vulnerable 12.0XG Vulnerable; first fixed in 12.3 12.3(26) 12.0XH Vulnerable; first fixed in 12.3 12.3(26) 12.0XI Releases prior to 12.0(4)XI2 are vulnerable, release 12.0(4)XI2 and later are not vulnerable; first fixed in 12.3 12.3(26) 12.0XJ Releases prior to 12.0(4)XJ5 are vulnerable, release 12.0(4)XJ5 and later are not vulnerable; first fixed in 12.3 12.3(26) 12.0XK Vulnerable; first fixed in 12.3 12.3(26) 12.0XL Not Vulnerable 12.0XM Not Vulnerable 12.0XN Vulnerable; first fixed in 12.3 12.3(26) 12.0XQ Vulnerable; first fixed in 12.3 12.3(26) 12.0XR Vulnerable; first fixed in 12.3 12.3(26) 12.0XS Not Vulnerable 12.0XV Not Vulnerable 12.0XW Not Vulnerable Affected 12.1-Based Releases First Fixed Release Recommended Release 12.1 Vulnerable; first fixed in 12.3 12.3(26) 12.1AA Vulnerable; first fixed in 12.3 12.3(26) 12.1AX Not Vulnerable 12.1AY Releases prior to 12.1(22)AY1 are vulnerable, release 12.1(22)AY1 and later are not vulnerable; 12.1(22)EA11 12.1AZ Not Vulnerable 12.1CX Not Vulnerable 12.1DA Not Vulnerable 12.1DB Releases prior to 12.1(4)DB1 are vulnerable, release 12.1(4)DB1 and later are not vulnerable; first fixed in 12.4 12.4(18a) 12.1DC Releases prior to 12.1(4)DC2 are vulnerable, release 12.1(4)DC2 and later are not vulnerable; first fixed in 12.4 12.4(18a) 12.1E 12.1(27b)E4 12.1EA Releases prior to 12.1(11)EA1 are vulnerable, release 12.1(11)EA1 and later are not vulnerable; 12.1(22)EA11 12.1EB Not Vulnerable 12.1EC Vulnerable; migrate to any release in 12.2BC 12.3(23)BC1 12.1EO Not Vulnerable 12.1EU Not Vulnerable 12.1EV Not Vulnerable 12.1EW Not Vulnerable 12.1EX Vulnerable; first fixed in 12.1E 12.1EY Not Vulnerable 12.1EZ Vulnerable; first fixed in 12.1E 12.1GA Vulnerable; first fixed in 12.3 12.3(26) 12.1GB Vulnerable; first fixed in 12.3 12.3(26) 12.1T Vulnerable; first fixed in 12.3 12.3(26) 12.1XA Vulnerable; first fixed in 12.3 12.3(26) 12.1XB Not Vulnerable 12.1XC Vulnerable; first fixed in 12.3 12.3(26) 12.1XD Vulnerable; first fixed in 12.3 12.3(26) 12.1XE Not Vulnerable 12.1XF Not Vulnerable 12.1XG Vulnerable; first fixed in 12.3 12.3(26) 12.1XH Vulnerable; first fixed in 12.3 12.3(26) 12.1XI Vulnerable; first fixed in 12.3 12.3(26) 12.1XJ Vulnerable; first fixed in 12.3 12.3(26) 12.1XK Not Vulnerable 12.1XL Not Vulnerable 12.1XM Vulnerable; first fixed in 12.3 12.3(26) 12.1XN Not Vulnerable 12.1XO Not Vulnerable 12.1XP Vulnerable; first fixed in 12.3 12.3(26) 12.1XQ Vulnerable; first fixed in 12.3 12.3(26) 12.1XR Not Vulnerable 12.1XS Vulnerable; first fixed in 12.3 12.3(26) 12.1XT Releases prior to 12.1(3)XT2 are vulnerable, release 12.1(3)XT2 and later are not vulnerable; first fixed in 12.3 12.3(26) 12.1XU Not Vulnerable 12.1XV Releases prior to 12.1(5)XV1 are vulnerable, release 12.1(5)XV1 and later are not vulnerable; first fixed in 12.3 12.3(26) 12.1XW Vulnerable; first fixed in 12.3 12.3(26) 12.1XX Vulnerable; first fixed in 12.3 12.3(26) 12.1XY Vulnerable; first fixed in 12.3 12.3(26) 12.1XZ Vulnerable; first fixed in 12.3 12.3(26) 12.1YA Vulnerable; first fixed in 12.3 12.3(26) 12.1YB Vulnerable; first fixed in 12.3 12.3(26) 12.1YC Not Vulnerable 12.1YD Vulnerable; first fixed in 12.3 12.3(26) 12.1YE Releases prior to 12.1(5)YE1 are vulnerable, release 12.1(5)YE1 and later are not vulnerable; first fixed in 12.3 12.3(26) 12.1YF Not Vulnerable 12.1YG Not Vulnerable 12.1YH Not Vulnerable 12.1YI Vulnerable; first fixed in 12.3 12.3(26) 12.1YJ Not Vulnerable Affected 12.2-Based Releases First Fixed Release Recommended Release 12.2 Vulnerable; first fixed in 12.3 12.3(26) 12.2B Vulnerable; first fixed in 12.4 12.4(18a) 12.2BC Not Vulnerable 12.2BW Vulnerable; first fixed in 12.3 12.3(26) 12.2BY Vulnerable; first fixed in 12.4 12.4(18a) 12.2BZ Not Vulnerable 12.2CX Not Vulnerable 12.2CY Not Vulnerable 12.2CZ Not Vulnerable 12.2DA Not Vulnerable 12.2DD Vulnerable; first fixed in 12.4 12.4(18a) 12.2DX Vulnerable; first fixed in 12.4 12.4(18a) 12.2EU Not Vulnerable 12.2EW Not Vulnerable 12.2EWA Not Vulnerable 12.2EX Releases prior to 12.2(20)EX are vulnerable, release 12.2(20)EX and later are not vulnerable; migrate to any release in 12.2SEA 12.2(40)EX1 12.2EY Not Vulnerable 12.2EZ Not Vulnerable 12.2FX Not Vulnerable 12.2FY Not Vulnerable 12.2FZ Not Vulnerable 12.2IXA Vulnerable; contact TAC 12.2IXB Vulnerable; contact TAC 12.2IXC Vulnerable; contact TAC 12.2IXD Vulnerable; contact TAC 12.2IXE Vulnerable; migrate to any release in 12.2IXF 12.2(18)IXF; Available on 31-MAR-08 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(25)S15 12.2(25)S15 12.2SB 12.2(28)SB10 12.2(31)SB9 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 Not Vulnerable 12.2SEA Not Vulnerable 12.2SEB Not Vulnerable 12.2SEC Not Vulnerable 12.2SED Not Vulnerable 12.2SEE Not Vulnerable 12.2SEF Not Vulnerable 12.2SEG Not Vulnerable 12.2SG 12.2(44)SG 12.2(44)SG 12.2SGA Not Vulnerable 12.2SL Not Vulnerable 12.2SM Not Vulnerable 12.2SO Not Vulnerable 12.2SRA 12.2(33)SRA6 12.2(33)SRA7 12.2SRB 12.2(33)SRB3; Available on 07-APR-2008 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 Releases prior to 12.2(29a)SV1 are vulnerable, release 12.2(29a)SV1 and later are not vulnerable; migrate to any release in 12.2SVA 12.2(29b)SV 12.2SVA Not Vulnerable 12.2SVC Not Vulnerable 12.2SVD Not Vulnerable 12.2SW Releases prior to 12.2(25)SW10 are vulnerable, release 12.2(25)SW10 and later are not vulnerable; 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)SXF12 12.2(18)SXF12a 12.2(18)SXF13 12.2SXH 12.2(33)SXH1 12.2(33)SXH2 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 12.2(8)TPC10d 12.2UZ Not Vulnerable 12.2XA Vulnerable; first fixed in 12.3 12.3(26) 12.2XB Vulnerable; first fixed in 12.3 12.3(26) 12.2XC Vulnerable; first fixed in 12.4 12.4(18a) 12.2XD Vulnerable; first fixed in 12.3 12.3(26) 12.2XE Not Vulnerable 12.2XF Not Vulnerable 12.2XG Vulnerable; first fixed in 12.3 12.3(26) 12.2XH Vulnerable; first fixed in 12.3 12.3(26) 12.2XI Not Vulnerable 12.2XJ Vulnerable; first fixed in 12.3 12.3(26) 12.2XK Vulnerable; first fixed in 12.3 12.3(26) 12.2XL Vulnerable; first fixed in 12.3 12.3(26) 12.2XM Vulnerable; first fixed in 12.3 12.3(26) 12.2XN 12.2(33)XN1 12.3(26) 12.2XO Not Vulnerable 12.2XQ Vulnerable; first fixed in 12.3 12.3(26) 12.2XR Not Vulnerable 12.2XS Not Vulnerable 12.2XT Vulnerable; first fixed in 12.3 12.3(26) 12.2XU Vulnerable; first fixed in 12.3 12.3(26) 12.2XV Vulnerable; first fixed in 12.3 12.3(26) 12.2XW Vulnerable; first fixed in 12.3 12.3(26) 12.2YA Releases prior to 12.2(4)YA8 are vulnerable, release 12.2(4)YA8 and later are not vulnerable; first fixed in 12.3 12.3(26) 12.2YB Vulnerable; first fixed in 12.3 12.3(26) 12.2YC Vulnerable; first fixed in 12.3 12.3(26) 12.2YD Vulnerable; first fixed in 12.4 12.4(18a) 12.2YE Vulnerable; first fixed in 12.2S 12.2(25)S15 12.2(31)SB11 12.2(33)SRC 12.2YF Vulnerable; first fixed in 12.3 12.3(26) 12.2YG Not Vulnerable 12.2YH Vulnerable; first fixed in 12.3 12.3(26) 12.2YJ Releases prior to 12.2(8)YJ1 are vulnerable, release 12.2(8)YJ1 and later are not 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 Vulnerable; first fixed in 12.2SXF 12.2(18)SXF13 12.2YP Not Vulnerable 12.2YQ Not Vulnerable 12.2YR Not Vulnerable 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 Releases prior to 12.2(11)YV1 are vulnerable, release 12.2(11)YV1 and later are not vulnerable; first fixed in 12.4 12.4(18a) 12.2YW Vulnerable; first fixed in 12.4 12.4(18a) 12.2YX Vulnerable; first fixed in 12.4 12.4(18a) 12.2YY Vulnerable; first fixed in 12.4 12.4(18a) 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 Vulnerable; first fixed in 12.4 12.4(18a) 12.2ZC Not Vulnerable 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 Not Vulnerable 12.2ZH Releases prior to 12.2(13)ZH6 are vulnerable, release 12.2(13)ZH6 and later are not vulnerable; first fixed in 12.4 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 Not Vulnerable 12.2ZU Vulnerable; first fixed in 12.2SXH 12.2(33)SXH2 12.2ZY 12.2(18)ZY2 12.2(18)ZY2 Affected 12.3-Based Releases First Fixed Release Recommended Release 12.3 12.3(24) 12.3(26) 12.3B Vulnerable; first fixed in 12.4 12.4(18a) 12.3BC Not Vulnerable 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 Not Vulnerable 12.3VA Vulnerable; contact TAC 12.3XA 12.3(2)XA7; Available on 31-MAR-2008 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)XE6; Available on 31-MAR-2008 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; Available on 16-JUN-2008 12.4(15)T4 12.4(18a) 12.3XH Vulnerable; first fixed in 12.4 12.4(18a) 12.3XI 12.3(7)XI11; Available on 18-SEP-2008 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)XR8; Available on 31-MAR-2008 12.3(7)XR8; Available on 31-MAR-08 12.3XS Not Vulnerable 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 Not Vulnerable 12.3YA Not Vulnerable 12.3YD Not Vulnerable 12.3YF Vulnerable; first fixed in 12.3YX 12.3(14)YX11 12.4(15)T4 12.3YG 12.3(8)YG7; Available on 16-JUN-2008 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 Vulnerable; first fixed in 12.4T 12.4(15)T4 12.3YM 12.3(14)YM12 12.3(14)YM12 12.3YQ Vulnerable; first fixed in 12.4T 12.4(15)T4 12.3YS 12.3(11)YS3; Available on 31-MAR-2008 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)YX11 12.3(14)YX11 12.3YZ 12.3(11)YZ3 Affected 12.4-Based Releases First Fixed Release Recommended Release 12.4 12.4(10c) 12.4(13e) 12.4(16b) 12.4(17) 12.4(3h) 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 Not Vulnerable 12.4MR Not Vulnerable 12.4SW Vulnerable; contact TAC 12.4(15)SW 12.4T 12.4(15)T2 12.4(6)T10 12.4(9)T7 12.4(15)T4 12.4XA Vulnerable; first fixed in 12.4T 12.4(15)T4 12.4XB 12.4(2)XB6 12.4XC Vulnerable; contact TAC 12.4XD 12.4(4)XD10 12.4(4)XD10 12.4XE 12.4(6)XE2 12.4(15)T4 12.4XF Not Vulnerable 12.4XG 12.4(9)XG2 12.4(9)XG2 12.4XJ Vulnerable; first fixed in 12.4T 12.4(15)T4 12.4XK Vulnerable; first fixed in 12.4T 12.4(15)T4 12.4XL 12.4(15)XL2 12.4(15)XL2 12.4XM Not Vulnerable 12.4XN Not Vulnerable 12.4XT 12.4(6)XT2 12.4(6)XT2 12.4XV 12.4(11)XV 12.4XW Vulnerable; contact TAC 12.4(11)XW6 12.4XY Not Vulnerable A special patch for Cisco IOS Software Modularity is also available and can be downloaded from the Cisco IOS Software Modularity Patch Navigator at http://tools.cisco.com/swdf/ionpn/jsp/main.jsp. Top of the section Close Section Workarounds The workaround consists of filtering UDP packets to port 2067 and IP protocol 91 packets. Filters can be applied at network boundaries to filter all IP protocol 91 packets and UDP packets to port 2067 or can be applied on individual affected devices to permit such traffic only from trusted peer IP addresses. However, since both of the protocols are connectionless, it is possible for an attacker to spoof malformed packets from legitimate peer IP addresses. As soon as DLSw is configured, the Cisco IOS device begins listening on IP protocol 91. However, this protocol is only used if DLSw is configured for Fast Sequenced Transport (FST). A DLSw FST peer configuration will contain the following line: dlsw remote-peer 0 fst If FST is used, filtering IP protocol 91 will break the operation, so filters need to permit protocol 91 traffic from legitimate peer IP addresses. It is possible to disable UDP processing in DLSw with the dlsw udp-disable command. However, disabling UDP only prevents the sending of UDP packets, it does not prevent the receiving and processing of incoming UDP packets. To protect a vulnerable device from malicious packets via UDP port 2067, both of the following actions must be taken: Disable UDP outgoing packets with the "dlsw udp-disable" command, AND Filter UDP 2067 in the vulnerable device using infrastructure ACL. 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-dlsw.shtml Using Control Plane Policing on Affected Devices Control Plane Policing (CoPP) can be used to block untrusted DLSw traffic to the device. Cisco IOS software releases 12.0S, 12.2SX, 12.2S, 12.3T, 12.4, and 12.4T support the 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 devices in accordance with existing security policies and configurations. The following example, which uses 192.168.100.1 to represent a trusted host, can be adapted to your network. If FST is not used, protocol 91 may be completely filtered. Additionally, if UDP is disabled with the dlsw udp-disable command, UDP port 2067 may also be completely filtered. !--- Deny DLSw traffic from trusted hosts to all IP addresses !--- configured on all interfaces of the affected device so that !--- it will be allowed by the CoPP feature access-list 111 deny udp host 192.168.100.1 any eq 2067 access-list 111 deny 91 host 192.168.100.1 any !--- Permit all other DLSw 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 111 permit udp any any eq 2067 access-list 111 permit 91 any any !--- Permit (Police or Drop)/Deny (Allow) all other Layer 3 and Layer 4 !--- 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-DLSw-class match access-group 111 !--- Create a Policy-Map that will be applied to the !--- Control-Plane of the device. policy-map drop-DLSw-traffic class drop-DLSw-class drop !--- Apply the Policy-Map to the Control-Plane of the !--- device control-plane service-policy input drop-DLSw-trafficIn the above CoPP example, the access control 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. Please note that in the Cisco IOS 12.2S and 12.0S trains the policy-map syntax is different: policy-map drop-DLSw-traffic class drop-DLSw-class police 32000 1500 1500 conform-action drop exceed-action dropAdditional information on the configuration and use of the CoPP feature is available at http://www.cisco.com/en/US/products/ps6642/products_white_paper0900aecd804fa16a.shtml and http://www.cisco.com/en/US/products/sw/iosswrel/ps1838/products_feature_guide09186 a008052446b.html. Using Infrastructure ACLs at Network Boundary Although it is often difficult to block traffic transiting your network, it is possible to identify traffic that should never be allowed to target your infrastructure devices and block that traffic at the border of your network. iACLs are 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 iACL example shown below should be included as part of the deployed infrastructure access-list that will protect all devices with IP addresses in the infrastructure IP address range. If FST is not used, protocol 91 may be completely filtered. Additionally, if UDP is disabled with the dlsw udp-disable command, UDP port 2067 may also be completely filtered. !--- Permit DLSw (UDP port 2067 and IP protocol 91) packets !--- from trusted hosts destined to infrastructure addresses. access-list 150 permit udp TRUSTED_HOSTS MASK INFRASTRUCTURE_ADDRESSES MASK eq 2067 access-list 150 permit 91 TRUSTED_HOSTS MASK INFRASTRUCTURE_ADDRESSES MASK !--- Deny DLSw (UDP port 2067 and IP protocol 91) packets from !--- all other sources destined to infrastructure addresses. access-list 150 deny udp any INFRASTRUCTURE_ADDRESSES MASK eq 2067 access-list 150 deny 91 any INFRASTRUCTURE_ADDRESSES MASK !--- Permit/deny all other Layer 3 and Layer 4 traffic in accordance !--- with existing security policies and configurations !--- Permit all other traffic to transit the device. access-list 150 permit ip any any interface serial 2/0 ip access-group 150 inThe white paper entitled "Protecting Your Core: Infrastructure Protection Access Control Lists" presents guidelines and recommended deployment techniques for infrastructure protection access lists. This white paper can be obtained at the following link: http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801a1a55.shtml Top of the section Close Section Obtaining Fixed Software Cisco has released free software updates that address these vulnerabilities. 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. These vulnerabilities were found internally. 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-dlsw.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 1.4 2008-April-25 Updated link to the CVSS score of CSCsk73104. Revision 1.3 2008-Apr-21 Added the specific link for IOS Software Modularity patch Revision 1.2 2008-Mar-31 Replacing IOS First Fixed Table with correct table -- data visible between 3/28 and 3/31was incorrect Revision 1.1 2008-Mar-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-Mar-26 Initial public release [***** End Cisco Security Advisory Document ID: 99758 *****] _______________________________________________________________________________ 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. 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