Summary

• Cisco IOS Software contains a queue wedge vulnerability that can be triggered when processing IP tunneled packets.  Only Cisco IOS Software running on the Cisco 10000 Series router has been demonstrated to be affected.
  
  Successful exploitation of this vulnerability may prevent traffic from transiting the affected interfaces.
  
  Cisco has released software updates that address this vulnerability.  There are no workarounds for this vulnerability.  This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120926-c10k-tunnels
  
  

  Note: The September 26, 2012, Cisco IOS Software Security Advisory bundled publication includes nine Cisco Security Advisories. Eight of the advisories address vulnerabilities in Cisco IOS Software, and one advisory addresses a vulnerability in Cisco Unified Communications Manager. Each Cisco IOS Software Security Advisory lists the Cisco IOS Software releases that correct the vulnerability or vulnerabilities detailed in the advisory as well as the Cisco IOS Software releases that correct all Cisco IOS Software vulnerabilities in the September 2012 bundled publication. 

  Individual publication links are in "Cisco Event Response: Semi-Annual Cisco IOS Software Security Advisory Bundled Publication" at the following link:

  http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep12.html

Affected Products

• 
  

  Vulnerable Products

  Cisco 10000 Series routers running Cisco IOS Software are potentially affected. See the "Details" section below for information on affected versions.
  
  A device has an affected configuration if the following conditions are true:
  
  

  • A tunnel interface is configured.  See the following sample to determine if a tunnel exists:

  Router#show ip interface brief
  Interface                  IP-Address      OK? Method Status                Protocol
  GigabitEthernet0/0         172.16.1.1      YES NVRAM  up                    up      
  GigabitEthernet0/1         172.16.2.1  YES NVRAM  up                    up      
  NVI0                       unassigned      YES unset  administratively down down    
  Tunnel0                    172.16.5.1         YES manual up                    up   
  

      A tunnel interface can be identified under the "Interface" column by the name "Tunnel#", where "#" indicates an interface number, i.e. "Tunnel0" as shown above.
  
  Note: A Cisco 10000 Series router may be vulnerable even if the tunnels are not explicitly configured.  Tunnels may be configured by other features and these tunnels are also potentially affected.
  
  

  • The tunnel mode is one of the following:

  a.  GRE/IP - tunnel mode gre ip
  b.  IPIP - tunnel mode ipip
  c.  IPv6inIP - tunnel mode ipv6ip
  

  The above tunnel modes would correspond to IPv4 protocol 47, 4 or 41 packets.
  

  Determining if your device is affected

  An interface queue wedge is a class of vulnerabilities in which certain packets are received and queued by a Cisco IOS router or switch, but due to a processing error, are never removed from the queue.

  Packets that are received by a device are counted against the interface input "queue," which is of a limited and relatively small size. For example, on most platforms the default interface input queue is 75 packets, which is a value that can be configured via the hold-queue value in the interface configuration command. Once the input queue contains nothing but packets that, due to a bug, will never be dequeued, the queue is said to be wedged. More recently this condition has been termed a "blocked interface."

  This condition can be viewed on a Cisco IOS device when the input queue size is equal to or greater than (depending on the Cisco IOS Software Release) the input queue max value, as shown below. In this example, the current "size" of the input queue is 75, which is equal to the "max" size of the input queue, which is also 75.

  Router#show interface Ethernet 0/0 | include queue
    Input queue: 75/75/44/0 (size/max/drops/flushes);
    Output queue: 0/40 (size/max)

  For more information about queue wedges and a few detection mechanisms that may be used to identify a blocked interface on Cisco IOS Software (including an Embedded Event Manager, or EEM, script specifically for this purpose and a whitepaper describing how this condition can be detected using SNMP) go to: http://blogs.cisco.com/security/comments/cisco_ios_queue_wedges_explained/

  To determine the Cisco IOS Software release that is running on a Cisco product, administrators can log in to the device and issue the show version command to display the system banner. The system banner confirms that the device is running Cisco IOS Software by displaying text similar to "Cisco Internetwork Operating System Software" or "Cisco IOS Software." The image name displays in parentheses, followed by "Version" and the Cisco IOS Software release name. Other Cisco devices do not have the show version command or may provide different output.

  The following example identifies a Cisco product that is running Cisco IOS Software Release 15.0(1)M1 with an installed image name of C3900-UNIVERSALK9-M:

  Router> show version 
  Cisco IOS Software, C3900 Software (C3900-UNIVERSALK9-M), Version 15.0(1)M1, RELEASE SOFTWARE (fc1)
  Technical Support: http://www.cisco.com/techsupport
  Copyright (c) 1986-2009 by Cisco Systems, Inc.
  Compiled Wed 02-Dec-09 17:17 by prod_rel_team

  !--- output truncated 

  Additional information about Cisco IOS Software release naming conventions is available in "White Paper: Cisco IOS and NX-OS Software Reference Guide" at http://www.cisco.com/web/about/security/intelligence/ios-ref.html.

  Products Confirmed Not Vulnerable

  No other Cisco products are currently known to be affected by this vulnerability.

Details

• Cisco IOS Software contains a queue wedge vulnerability that can be triggered when processing tunneled packets.  Only Cisco IOS Software running on the Cisco 10000 Series router has been demonstrated to be affected.
  
  The queue wedge may be triggered when processing ingress IP tunneled packets. The packets that trigger the vulnerability are tunneled IP packets of the following types: GRE/IP, IPIP, and IPv6 in IPv4 packets, for tunnels that terminate at the router. Transit traffic does not cause this vulnerability to be triggered.
  
  Successful exploitation of this vulnerability may result in an inability to pass traffic on affected interfaces.
  
  This vulnerability is described in Cisco bug ID CSCts66808 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2012-4620
  
  

Workarounds

• There are no workarounds for this vulnerability.

Fixed Software

• When considering software upgrades, customers are advised to consult the Cisco Security Advisories and Responses archive at http://www.cisco.com/go/psirt and review subsequent advisories to determine exposure and a complete upgrade solution.

  In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.

  
  

  Cisco IOS Software

  Each row of the following Cisco IOS Software table corresponds to a Cisco IOS Software train. If a particular train is vulnerable, the earliest releases that contain the fix are listed in the First Fixed Release column. The First Fixed Release for All Advisories in the September 2012 Bundled Publication column lists the earliest possible releases that correct all the published vulnerabilities in the Cisco IOS Software Security Advisory bundled publication. Cisco recommends upgrading to the latest available release, where possible.

  The Cisco IOS Software Checker allows customers to search for Cisco Security Advisories that address specific Cisco IOS Software releases. This tool is available on the Cisco Security (SIO) portal at https://sec.cloudapps.cisco.com/security/center/selectIOSVersion.x

  
  
  

  Major Release	Availability of Repaired Releases
  Affected 12.0-Based Releases	First Fixed Release	First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
  There are no affected 12.0 based releases
  Affected 12.2-Based Releases	First Fixed Release	First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
  12.2	Not vulnerable	Not vulnerable
  12.2B	Not vulnerable	Vulnerable; First fixed in Release 12.4 Releases up to and including 12.2(4)B8 are not vulnerable.
  12.2BC	Not vulnerable	Not vulnerable
  12.2BW	Not vulnerable	Not vulnerable
  12.2BX	Not vulnerable	12.2(15)BX Releases up to and including 12.2(2)BX1 are not vulnerable.
  12.2BY	Not vulnerable	Not vulnerable
  12.2BZ	Not vulnerable	Not vulnerable
  12.2CX	Not vulnerable	Not vulnerable
  12.2CY	Not vulnerable	Not vulnerable
  12.2CZ	Not vulnerable	Vulnerable; migrate to any release in 12.2S
  12.2DA	Not vulnerable	Not vulnerable
  12.2DD	Not vulnerable	Not vulnerable
  12.2DX	Not vulnerable	Not vulnerable
  12.2EU	Not vulnerable	Not vulnerable
  12.2EW	Not vulnerable	Not vulnerable
  12.2EWA	Not vulnerable	Not vulnerable
  12.2EX	Not vulnerable	Vulnerable; First fixed in Release 15.0SE Releases up to and including 12.2(37)EX are not vulnerable.
  12.2EY	Not vulnerable	Vulnerable; First fixed in Release 15.1EY Releases up to and including 12.2(46)EY are not vulnerable.
  12.2EZ	Not vulnerable	Not vulnerable
  12.2FX	Not vulnerable	Not vulnerable
  12.2FY	Not vulnerable	Not vulnerable
  12.2FZ	Not vulnerable	Not vulnerable
  12.2IRA	Not vulnerable	Vulnerable; First fixed in Release 12.2SRE
  12.2IRB	Not vulnerable	Vulnerable; First fixed in Release 12.2SRE
  12.2IRC	Not vulnerable	Vulnerable; First fixed in Release 12.2SRE
  12.2IRD	Not vulnerable	Vulnerable; First fixed in Release 12.2SRE
  12.2IRE	Not vulnerable	Vulnerable; First fixed in Release 12.2SRE
  12.2IRF	Not vulnerable	Vulnerable; First fixed in Release 12.2SRE
  12.2IRG	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2IRH	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2IRI	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2IXA	Not vulnerable	Not vulnerable
  12.2IXB	Not vulnerable	Not vulnerable
  12.2IXC	Not vulnerable	Not vulnerable
  12.2IXD	Not vulnerable	Not vulnerable
  12.2IXE	Not vulnerable	Not vulnerable
  12.2IXF	Not vulnerable	Not vulnerable
  12.2IXG	Not vulnerable	Not vulnerable
  12.2IXH	Not vulnerable	Not vulnerable
  12.2JA	Not vulnerable	Not vulnerable
  12.2JK	Not vulnerable	Not vulnerable
  12.2MB	Not vulnerable	Not vulnerable
  12.2MC	Not vulnerable	Releases up to and including 12.2(15)MC1 are not vulnerable. Releases 12.2(15)MC2b and later are not vulnerable. First fixed in Release 12.4
  12.2MRA	Not vulnerable	Vulnerable; First fixed in Release 12.2SRE
  12.2MRB	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2S	Not vulnerable	Not vulnerable
  12.2SB	Vulnerable; only releases 12.2(33)SB through 12.2(33)SB11 are vulnerable	12.2(33)SB13
  12.2SBC	Not vulnerable	Vulnerable; First fixed in Release 12.2SB
  12.2SCA	Not vulnerable	Vulnerable; First fixed in Release 12.2SCF
  12.2SCB	Not vulnerable	Vulnerable; First fixed in Release 12.2SCF
  12.2SCC	Not vulnerable	Vulnerable; First fixed in Release 12.2SCF
  12.2SCD	Not vulnerable	Vulnerable; First fixed in Release 12.2SCF
  12.2SCE	Not vulnerable	Vulnerable; First fixed in Release 12.2SCF
  12.2SCF	Not vulnerable	12.2(33)SCF4
  12.2SCG	Not vulnerable	Not vulnerable
  12.2SE	Not vulnerable	12.2(46)SE1 12.2(55)SE6
  12.2SEA	Not vulnerable	Not vulnerable
  12.2SEB	Not vulnerable	Not vulnerable
  12.2SEC	Not vulnerable	Not vulnerable
  12.2SED	Not vulnerable	Not vulnerable
  12.2SEE	Not vulnerable	Not vulnerable
  12.2SEF	Not vulnerable	Not vulnerable
  12.2SEG	Not vulnerable	Not vulnerable
  12.2SG	Not vulnerable	12.2(53)SG8 Vulnerable; releases up to and including 12.2(46)SG1 are not vulnerable.
  12.2SGA	Not vulnerable	Not vulnerable
  12.2SM	Not vulnerable	Not vulnerable
  12.2SO	Not vulnerable	Not vulnerable
  12.2SQ	Not vulnerable	Releases up to and including 12.2(44)SQ2 are not vulnerable.
  12.2SRA	Not vulnerable	Not vulnerable
  12.2SRB	Not vulnerable	Not vulnerable
  12.2SRC	Note: Releases prior to 12.2(33)SRC2 are vulnerable; Releases 12.2(33)SRC2 and later are not vulnerable.	Vulnerable; First fixed in Release 12.2SRE
  12.2SRD	Note: Releases prior to 12.2(33)SRD1 are vulnerable; Releases 12.2(33)SRD1 and later are not vulnerable.	Vulnerable; First fixed in Release 12.2SRE
  12.2SRE	Not vulnerable	12.2(33)SRE7
  12.2STE	Not vulnerable	Not vulnerable
  12.2SU	Not vulnerable	Not vulnerable
  12.2SV	Not vulnerable	Not vulnerable
  12.2SVA	Not vulnerable	Not vulnerable
  12.2SVC	Not vulnerable	Not vulnerable
  12.2SVD	Not vulnerable	Not vulnerable
  12.2SVE	Not vulnerable	Not vulnerable
  12.2SW	Not vulnerable	Not vulnerable
  12.2SX	Not vulnerable	Not vulnerable
  12.2SXA	Not vulnerable	Not vulnerable
  12.2SXB	Not vulnerable	Not vulnerable
  12.2SXD	Not vulnerable	Not vulnerable
  12.2SXE	Not vulnerable	Not vulnerable
  12.2SXF	Not vulnerable	Not vulnerable
  12.2SXH	Not vulnerable	Vulnerable; releases up to and including 12.2(33)SXH7 are not vulnerable
  12.2SXI	Not vulnerable	12.2(33)SXI10
  12.2SXJ	Not vulnerable	12.2(33)SXJ4
  12.2SY	Not vulnerable	12.2(50)SY3
  12.2SZ	Not vulnerable	Not vulnerable
  12.2T	Not vulnerable	Vulnerable; First fixed in Release 12.4 Releases up to and including 12.2(8)T10 are not vulnerable.
  12.2TPC	Not vulnerable	Not vulnerable
  12.2WO	Not vulnerable	Vulnerable; First fixed in Release 15.0SG
  12.2XA	Not vulnerable	Not vulnerable
  12.2XB	Not vulnerable	Not vulnerable
  12.2XC	Not vulnerable	Not vulnerable
  12.2XD	Not vulnerable	Not vulnerable
  12.2XE	Not vulnerable	Not vulnerable
  12.2XF	Not vulnerable	Not vulnerable
  12.2XG	Not vulnerable	Not vulnerable
  12.2XH	Not vulnerable	Not vulnerable
  12.2XI	Not vulnerable	Not vulnerable
  12.2XJ	Not vulnerable	Not vulnerable
  12.2XK	Not vulnerable	Not vulnerable
  12.2XL	Not vulnerable	Not vulnerable
  12.2XM	Not vulnerable	Not vulnerable
  12.2XNA	Please see Cisco IOS-XE Software Availability	Please see Cisco IOS-XE Software Availability
  12.2XNB	Please see Cisco IOS-XE Software Availability	Please see Cisco IOS-XE Software Availability
  12.2XNC	Please see Cisco IOS-XE Software Availability	Please see Cisco IOS-XE Software Availability
  12.2XND	Please see Cisco IOS-XE Software Availability	Please see Cisco IOS-XE Software Availability
  12.2XNE	Please see Cisco IOS-XE Software Availability	Please see Cisco IOS-XE Software Availability
  12.2XNF	Please see Cisco IOS-XE Software Availability	Please see Cisco IOS-XE Software Availability
  12.2XO	Not vulnerable	Vulnerable; First fixed in Release 12.2SG Releases up to and including 12.2(40)XO are not vulnerable.
  12.2XQ	Not vulnerable	Not vulnerable
  12.2XR	Not vulnerable	Not vulnerable
  12.2XS	Not vulnerable	Not vulnerable
  12.2XT	Not vulnerable	Not vulnerable
  12.2XU	Not vulnerable	Not vulnerable
  12.2XV	Not vulnerable	Not vulnerable
  12.2XW	Not vulnerable	Not vulnerable
  12.2YA	Not vulnerable	Not vulnerable
  12.2YC	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2YD	Not vulnerable	Not vulnerable
  12.2YE	Not vulnerable	Not vulnerable
  12.2YK	Not vulnerable	Not vulnerable
  12.2YO	Not vulnerable	Not vulnerable
  12.2YP	Not vulnerable	Not vulnerable
  12.2YT	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2YW	Not vulnerable	Not vulnerable
  12.2YX	Not vulnerable	Not vulnerable
  12.2YY	Not vulnerable	Not vulnerable
  12.2YZ	Not vulnerable	Not vulnerable
  12.2ZA	Not vulnerable	Not vulnerable
  12.2ZB	Not vulnerable	Not vulnerable
  12.2ZC	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2ZD	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2ZE	Not vulnerable	Vulnerable; First fixed in Release 12.4
  12.2ZH	Not vulnerable	Vulnerable; First fixed in Release 12.4
  12.2ZJ	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2ZP	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2ZU	Not vulnerable	Not vulnerable
  12.2ZX	Not vulnerable	Vulnerable; First fixed in Release 12.2SB
  12.2ZY	Not vulnerable	Not vulnerable
  12.2ZYA	Not vulnerable	Not vulnerable
  Affected 12.3-Based Releases	First Fixed Release	First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
  There are no affected 12.3 based releases
  Affected 12.4-Based Releases	First Fixed Release	First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
  There are no affected 12.4 based releases
  Affected 15.0-Based Releases	First Fixed Release	First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
  15.0EX	Not vulnerable	Not vulnerable
  15.0EY	Not vulnerable	Not vulnerable
  15.0M	Not vulnerable	15.0(1)M9
  15.0MR	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  15.0MRA	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  15.0S	15.0(1)S5 Cisco IOS XE devices: Please see Cisco IOS XE Software Availability	15.0(1)S6 Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
  15.0SE	Not vulnerable	15.0(2)SE
  15.0SG	Not vulnerable Cisco IOS XE devices: Please see Cisco IOS XE Software Availability	15.0(2)SG5 15.0(2)SG6; Available on 11-OCT-12 Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
  15.0SY	Not vulnerable	15.0(1)SY2
  15.0XA	Not vulnerable	Vulnerable; First fixed in Release 15.1M
  15.0XO	Cisco IOS XE devices: Please see Cisco IOS-XE Software Availability	Cisco IOS XE devices: Please see Cisco IOS-XE Software Availability
  Affected 15.1-Based Releases	First Fixed Release	First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
  15.1EY	Not vulnerable	15.1(2)EY4
  15.1GC	Not vulnerable	Vulnerable; First fixed in Release 15.1M
  15.1M	Not vulnerable	15.1(4)M5
  15.1MR	Not vulnerable	15.1(3)MR; Available on 01-OCT-12
  15.1S	Not vulnerable Cisco IOS XE devices: Please see Cisco IOS XE Software Availability	15.1(3)S Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
  15.1SG	Not vulnerable Cisco IOS XE devices: Please see Cisco IOS XE Software Availability	15.1(1)SG1 15.1(2)SG 12-NOV-12 Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
  15.1SNG	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  15.1SNH	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  15.1SNI	Not vulnerable	Vulnerable; migrate to any release in 15.2SNG
  15.1SV	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  15.1T	Not vulnerable	Vulnerable; First fixed in Release 15.1M
  15.1XB	Not vulnerable	Vulnerable; First fixed in Release 15.1M
  Affected 15.2-Based Releases	First Fixed Release	First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
  15.2GC	Not vulnerable	Releases prior to 15.2(3)GC are vulnerable; Releases 15.2(3)GC and later are not vulnerable. First fixed in Release 15.2T
  15.2JA	Not vulnerable	Not Vulnerable
  15.2M	Not vulnerable	Not vulnerable
  15.2S	Not vulnerable Cisco IOS XE devices: Please see Cisco IOS XE Software Availability	15.2(1)S2 15.2(2)S1 15.2(4)S Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
  15.2SNG	Not vulnerable	Not vulnerable
  15.2T	Not vulnerable	15.2(1)T3 15.2(2)T2 15.2(3)T2; Available on 12-OCT-12

  
  

  Cisco IOS XE Software

  Cisco IOS XE Software is not affected by the vulnerability that is disclosed in this document.
  
  
  

  Cisco IOS XR Software

  Cisco IOS XR Software is not affected by the vulnerability that is disclosed in this document.

Exploitation and Public Announcements

• The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

  This vulnerability was found during troubleshooting of a customer issue.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120926-c10k-tunnels

Revision History

• Revision 1.1	2013-January-18	Corrected software table placement.
  Revision 1.0	2012-September-26	Initial public release.

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