__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Cisco IOS User Datagram Protocol Delivery Issue for IPv4/IPv6 Dual-Stack Routers [Cisco Security Advisory Document ID: 100638] March 27, 2008 19:00 GMT Number S-244 [REVISED 2 Apr 2008] ______________________________________________________________________________ PROBLEM: A device running Cisco IOS software that has Internet Protocol version 6 (IPv6) enabled may be subject to a denial of service (DoS) attack. PLATFORM: Only Cisco IOS software releases that have IPv6 enabled are affected by this vulnerability. DAMAGE: DoS. SOLUTION: Upgrade to the appropriate version. ______________________________________________________________________________ VULNERABILITY The risk is LOW. Successful exploitation of the vulnerability ASSESSMENT: can result in the device crashing if RSVP service is configured on the interface or any other affected IPv4 UDP-based service will prevent the interface from receiving additional traffic. ______________________________________________________________________________ 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-244.shtml ORIGINAL BULLETIN: http://www.cisco.com/en/US/products/products_security_ advisory09186a008096986d.shtml CVE: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name= CVE-2008-1153 ______________________________________________________________________________ REVISION HISTORY: 04/02/2008 - revised S-244 to reflect changes Cisco has made in Cisco Security Advisory Document ID: 100638 where they added workaround using rACL for Cisco routers 12000, 7500 and 10720 series; 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. [***** Start Cisco Security Advisory Document ID: 100638 *****] Cisco Security Advisory: Cisco IOS User Datagram Protocol Delivery Issue For IPv4/IPv6 Dual-stack Routers Document ID: 100638 Advisory ID: cisco-sa-20080326-IPv4IPv6 http://www.cisco.com/warp/public/707/cisco-sa-20080326-IPv4IPv6.shtml Revision 1.2 Last Updated 2008 April 1 1930 UTC (GMT) For Public Release 2008 March 26 1600 UTC (GMT) -------------------------------------------------------------------------------- Cisco Security Advisory: Cisco IOS User Datagram Protocol Delivery Issue For IPv4/IPv6 Dual-stack Routers Summary A device running Cisco IOS software that has Internet Protocol version 6 (IPv6) enabled may be subject to a denial of service (DoS) attack. For the device to be affected by this vulnerability the device also has to have certain Internet Protocol version 4 (IPv4) User Datagram Protocol (UDP) services enabled. To exploit this vulnerability an offending IPv6 packet must be targeted to the device. Packets that are routed throughout the router can not trigger this vulnerability. Successful exploitation will prevent the interface from receiving any additional traffic. The only exception is Resource Reservation Protocol (RSVP) service, which if exploited, will cause the device to crash. Only the interface on which the vulnerability was exploited will be affected. Cisco is providing fixed software to address this issue. There are workarounds available to mitigate the effects of the vulnerability. This advisory is posted at http://www.cisco.com/warp/public/707/cisco-sa-20080326-IPv4IPv6.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 Only Cisco IOS software releases that have IPv6 enabled are affected by this vulnerability. In order to be vulnerable both support for IPv6 protocol and IPv4 UDP-based services must be enabled on the device. The IPv6 is not enabled by default in Cisco IOS software. To determine the software running on a Cisco IOS 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 Cisco IOS software release name. Other Cisco devices will not have the show version command, or will give different output. The following example shows output from a device running a Cisco IOS image: Router>show version Cisco IOS Software, 1841 Software (C1841-ADVSECURITYK9-M), Version 12.4(15)T2, RELEASE SOFTWARE (fc7) Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2008 by Cisco Systems, Inc. Compiled Thu 17-Jan-08 23:12 by prod_rel_teamAdditional information about Cisco IOS software release naming is available at the following link: http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_white_paper 09186a008018305e.shtml. In order for an interface to be vulnerable two conditions must be satisfied: An interface must have IPv6 enabled. One or more of the following IPv4 UDP-based services must be enabled: TACACS - port 49 Domain Name System (DNS) server - port 53 Resource Reservation Protocol (RSVP) - port 1698 Layer Two Forwarding (L2F)/Layer Two Tunnel Protocol (L2TP) - port 1701 IP SLA Responder - port 1967 Media Gateway Control Protocol (MGCP) - port 2427 Session Initiation Protocol (SIP) - port 5060 No other IPv4 UDP-based services are known to be affected. How To Verify If IPv6 Is Enabled IPv6 protocol is enabled on an interface if either or both of the following configuration lines are present in the configuration: Router#show running-config interface FastEthernet0/1 ipv6 address 2001:0DB8:C18:1::/64 eui-64Router#show running-config interface FastEthernet0/1 ipv6 enabledIf any of the interfaces contain either or both of the ipv6 lines then IPv6 is enabled on that particular interface. How To Verify If IPv4 UDP-based Services Are Enabled To determine whether device is affected or not, use the show ip sockets command to display all UDP ports device is listening to. In some newer IOS releases the command show ip sockets is obsoleted, and the alternate command show udp can be used instead. The output is identical to the show ip sockets command. The device is vulnerable if the Local Port column (fifth from the left) in the output of show ip sockets contains any of the port numbers listed in the example below. Router#show ip sockets Proto Remote Port Local Port In Out Stat TTY OutputIF 17 192.168.100.1 49 192.168.100.2 49 0 0 11 0 17 0.0.0.0 0 192.168.100.2 53 0 0 211 0 17 --listen-- 192.168.100.2 1698 0 0 1 0 17 192.168.100.1 1701 192.168.100.2 1701 1 0 1021 0 17 0.0.0.0 0 192.168.100.2 1967 0 0 211 0 17 0.0.0.0 0 --any-- 2427 0 0 211 0 17 0.0.0.0 0 --any-- 5060 0 0 211 0 Products Confirmed Not Vulnerable No other Cisco products are currently known to be affected by this vulnerability. Any device running Cisco IOS without IPv6 enabled is not vulnerable. Cisco IOS XR and Cisco PIX/ASA are not affected. Top of the section Close Section Details To exploit this vulnerability an offending IPv6 packet must be targeted to the device. Packets that are routed throughout the router can not trigger this vulnerability. Successful exploitation of the vulnerability may result in one of the following two conditions: The device will crash if RSVP service is configured on the interface. Any other affected IPv4 UDP-based service will prevent the interface from receiving additional traffic. Only the interface on which the vulnerability is exploited will be affected. This vulnerability is independent of the interface media type. A blocked interface will immediately stop receiving any subsequent packets destined to the device itself until it is unblocked. It is possible to unblock the interface using methods other than a device reload. These methods are described in the Workarounds section. All other interfaces are unaffected and will continue receiving and transmitting packets. Blocked interface may allow transit traffic to flow for a period of time. Transit traffic may continue to flow until either the respective routing entry or Address Resolution Protocol (ARP) entry expires, whichever event occurs first. Depending on the circumstances the transit traffic can stop flowing through the blocked interface within a few seconds or continue up to four hours (which is the ARP cache default lifetime). After that no further transit traffic will flow through the blocked interface. No other IPv4 UDP-based services are known to be affected by this vulnerability. This vulnerability is documented in Cisco Bug ID CSCse56501, and has been assigned the Common Vulnerabilities and Exposures (CVE) ID CVE-2008-1153. Identification Of Vulnerability Exploitation The show interfaces command can be used to view the input queue size to identify a blocked input interface. A device under attack, but not yet blocked will show the Input queue size increasing without a subsequent decrease. If the current size (in this case, 76) is larger than the maximum size (75), the input queue is blocked. The value of 75 is the default value and it can be changed using the interface command hold-queue X in . Router#show interfaces FastEthernet 0/1 | include queue Input queue: 76/75/0/0 (size/max/drops/flushes); Total output drops: 0 Output queue: 0/40 (size/max)The example above shows that the interface FastEthernet0/1 is blocked. The show ip sockets command can be used to determine which protocol blocks the interface. If In column (sixth from the left) of the output contains any other number than zero (0) that is an indication that packets of that particular protocol are blocking, or starting to block, the interface. The following example shows DNS packets that are beginning to fill the input queue of the interface. The interface is not completely blocked because only 13 packets are in the input queue. Router#show ip sockets Proto Remote Port Local Port In Out Stat TTY OutputIF 17 192.168.100.1 49 192.168.100.2 49 0 0 11 0 17 0.0.0.0 0 192.168.100.2 53 13 0 211 0 17 --listen-- 192.168.100.2 1698 0 0 1 0 17 192.168.100.1 1701 192.168.100.2 1701 1 0 1021 0 17 0.0.0.0 0 192.168.100.2 1967 0 0 211 0 17 0.0.0.0 0 --any-- 2427 0 0 211 0 17 0.0.0.0 0 --any-- 5060 0 0 211 0 The output of the show ip sockets command does not provide information on interfaces. It is possible that packets from multiple protocols may be blocking a single interface. The output of the command must be interpreted with the device's configuration to establish the affected port. Additional methods that can be used to detect blocked interfaces are described in "Cisco Applied Mitigation Bulletin: User Datagram Protocol Delivery Issue For IPv4/IPv6 Dual-Stack Routers" document available at http://www.cisco.com/warp/public/707/cisco-amb-20080326-IPv4IPv6.shtml. The method utilizes Embedded Event Manager (EEM) and Applets or an EEM Script. 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. UDP delivery issue when IPv4 and IPv6 are bound to the same socket Calculate the environmental score of CSCse56501 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 the vulnerability can result in one of the following two conditions: The device will crash if RSVP service is configured on the interface. Any other affected IPv4 UDP-based service will prevent the interface from receiving additional traffic. Only the interface on which the vulnerability is exploited will be affected. 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 Vulnerable; contact TAC 12.0SC Not Vulnerable 12.0SL Not Vulnerable 12.0SP Not Vulnerable 12.0ST Not Vulnerable 12.0SX Not Vulnerable 12.0SY Vulnerable; contact TAC 12.0SZ Vulnerable; contact TAC 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 12.1 Not Vulnerable 12.1AA Not Vulnerable 12.1AX Not Vulnerable 12.1AY Not Vulnerable 12.1AZ Not Vulnerable 12.1CX Not Vulnerable 12.1DA Not Vulnerable 12.1DB Not Vulnerable 12.1DC Not Vulnerable 12.1E Not Vulnerable 12.1EA Not Vulnerable 12.1EB Not Vulnerable 12.1EC Not Vulnerable 12.1EO Not Vulnerable 12.1EU Not Vulnerable 12.1EV Not Vulnerable 12.1EW Not Vulnerable 12.1EX Not Vulnerable 12.1EY Not Vulnerable 12.1EZ Not Vulnerable 12.1GA Not Vulnerable 12.1GB Not Vulnerable 12.1T Not Vulnerable 12.1XA Not Vulnerable 12.1XB Not Vulnerable 12.1XC Not Vulnerable 12.1XD Not Vulnerable 12.1XE Not Vulnerable 12.1XF Not Vulnerable 12.1XG Not Vulnerable 12.1XH Not Vulnerable 12.1XI Not Vulnerable 12.1XJ Not Vulnerable 12.1XK Not Vulnerable 12.1XL Not Vulnerable 12.1XM Not Vulnerable 12.1XN Not Vulnerable 12.1XO Not Vulnerable 12.1XP Not Vulnerable 12.1XQ Not Vulnerable 12.1XR Not Vulnerable 12.1XS Not Vulnerable 12.1XT Not Vulnerable 12.1XU Vulnerable; first fixed in 12.3 12.3(26) 12.1XV Vulnerable; first fixed in 12.3 12.3(26) 12.1XW Not Vulnerable 12.1XX Not Vulnerable 12.1XY Not Vulnerable 12.1XZ Not Vulnerable 12.1YA Not Vulnerable 12.1YB Vulnerable; first fixed in 12.3 12.3(26) 12.1YC Vulnerable; first fixed in 12.3 12.3(26) 12.1YD Vulnerable; first fixed in 12.3 12.3(26) 12.1YE Releases prior to 12.1(5)YE6 are vulnerable, release 12.1(5)YE6 and later are not vulnerable; first fixed in 12.3 12.3(26) 12.1YF Vulnerable; first fixed in 12.3 12.3(26) 12.1YG Not Vulnerable 12.1YH Vulnerable; first fixed in 12.3 12.3(26) 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 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 Vulnerable; first fixed in 12.3 12.3(26) 12.2BY Vulnerable; first fixed in 12.4 12.4(18a) 12.2BZ Vulnerable; first fixed in 12.3XI 12.2CX Vulnerable; first fixed in 12.3BC 12.3(23)BC1 12.2CY Vulnerable; first fixed in 12.3BC 12.3(23)BC1 12.2CZ Vulnerable; contact TAC 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 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(35)EX1 12.2(37)EX 12.2(40)EX1 12.2EY 12.2(37)EY 12.2EZ Vulnerable; first fixed in 12.2SEE 12.2FX Vulnerable; first fixed in 12.2SEE 12.2FY Vulnerable; first fixed in 12.2SEG 12.2(25)SEG4 12.2FZ Vulnerable; first fixed in 12.2SE 12.2(44)SE1 12.2IXA Vulnerable; contact TAC 12.2IXB Vulnerable; contact TAC 12.2IXC Vulnerable; contact TAC 12.2IXD Vulnerable; contact TAC 12.2IXE Not Vulnerable 12.2JA Vulnerable; first fixed in 12.3JA 12.2JK Vulnerable; first fixed in 12.4T 12.4(15)T4 12.2MB Vulnerable; contact TAC 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 12.2(25)SEF3 12.2(44)SE1 12.2SEG 12.2(25)SEG3 12.2(25)SEG4 12.2SG 12.2(25)SG3 12.2(31)SG3 12.2(37)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 Vulnerable; contact TAC 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 Vulnerable; contact TAC 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)SXF10a 12.2(18)SXF12a 12.2(18)SXF9 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 12.2(8)TPC10b 12.2UZ Vulnerable; first fixed in 12.2SB; Available on 31-MAR-2008 12.2(31)SB11 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 Vulnerable; first fixed in 12.3 12.3(26) 12.2XF Vulnerable; first fixed in 12.3BC 12.3(23)BC1 12.2XG Vulnerable; first fixed in 12.3 12.3(26) 12.2XH Vulnerable; first fixed in 12.3 12.3(26) 12.2XI Vulnerable; first fixed in 12.3 12.3(26) 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 Vulnerable; first fixed in 12.3 12.3(26) 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 12.2(4)YA13; Available on 31-MAR-2008 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 Vulnerable; first fixed in 12.3 12.3(26) 12.2YH Vulnerable; first fixed in 12.3 12.3(26) 12.2YJ Vulnerable; first fixed in 12.3 12.3(26) 12.2YK Vulnerable; first fixed in 12.4 12.4(18a) 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 Vulnerable; first fixed in 12.3 12.3(26) 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 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 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 Not Vulnerable Affected 12.3-Based Releases First Fixed Release Recommended Release 12.3 12.3(17c) 12.3(18a) 12.3(19a) 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 12.3(11)JA4 12.3(7)JA5 12.3JEA 12.3(8)JEA2 12.3(8)JEA4 12.3JEB 12.3(8)JEB1 12.3(8)JEB2 12.3JEC Not Vulnerable 12.3JK 12.3(2)JK3 12.3(8)JK 12.3(8)JK1 12.3JL 12.3(2)JL2 12.3(2)JL4 12.3JX 12.3(7)JX9 12.3(7)JX10 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)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 12.4(15)T4 12.4(18a) 12.3XH Vulnerable; first fixed in 12.4 12.4(18a) 12.3XI 12.3(7)XI10 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)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)YX8 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(12) 12.4(3h) 12.4(5c) 12.4(7e) 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 12.4(12)MR 12.4(16)MR2 12.4SW 12.4(11)SW3 12.4(15)SW 12.4T 12.4(11)T2 12.4(15)T 12.4(2)T6 12.4(4)T8 12.4(6)T8 12.4(9)T3 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)XD7 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 12.4(11)XJ4 12.4(15)T4 12.4XK Not Vulnerable 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 Interface Access Control List By deploying an IPv6 Access Control List (ACL) it is possible to prevent offending IPv6 packets reaching vulnerable UDP services. The ACL in the following example will block all IPv6 traffic from reaching vulnerable services. Router(config)#ipv6 access-list protect_IPv4_services Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq tacacs Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq domain Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq 1698 Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq 1701 Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq 1967 Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq 2427 Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq 5060 !--- Permit/deny all other Layer 3 and Layer 4 traffic in accordance !--- with existing security policies and configurations ! !--- Allow all other IPv6 traffic Router(config-ipv6-acl)#permit ipv6 any 2001:db8:1:128::/64 ! ! Router(config)#interface FastEthernet0/1 Router(config-if)#ipv6 traffic-filter protect_IPv4_services inReceive Access Control List Receive Access Lists (rACL) are a feature available on the following hardware models: Cisco 12000 Series, Cisco 7500 Series and Cisco 10720 Router. By deploying rACL it is possible to prevent offending IPv6 packets from reaching vulnerable UDP services. The rACL in the following example will block all IPv6 traffic from reaching vulnerable services. Router(config)#ipv6 access-list rACL Router(config-ipv6-acl)#deny udp any any eq tacacs Router(config-ipv6-acl)#deny udp any any eq domain Router(config-ipv6-acl)#deny udp any any eq 1698 Router(config-ipv6-acl)#deny udp any any eq 1701 Router(config-ipv6-acl)#deny udp any any eq 1967 Router(config-ipv6-acl)#deny udp any any eq 2427 Router(config-ipv6-acl)#deny udp any any eq 5060 !--- Allow all other IPv6 traffic Router(config-ipv6-acl)#permit ipv6 any any Router(config)#ipv6 receive access-list rACLAdditional Mitigation Techniques 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-IPv4IPv6.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 encountered in customer networks. 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-IPv4IPv6.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-bulletin@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 1.2 2008-April-01 Added workaround using rACL for Cisco routers 12000, 7500 and 10720 series. 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: 100638 *****] _______________________________________________________________________________ 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