Summary

• A vulnerability in the Internet Key Exchange (IKE) protocol of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a memory leak that could lead to a device reload.
  
  The vulnerability is due to incorrect handling of malformed IKE packets by the affected software. An attacker could exploit this vulnerability by sending crafted IKE packets to a device configured with features that leverage IKE version 1 (IKEv1).
  
  Although IKEv1 is automatically enabled on a Cisco IOS Software and Cisco IOS XE Software when IKEv1 or IKE version 2 (IKEv2) is configured, the vulnerability can be triggered only by sending a malformed IKEv1 packet.
  
  In specific conditions, normal IKEv1 packets can also cause an affected release of Cisco IOS Software to leak memory.
  
  Only IKEv1 is affected by this vulnerability.
  
  An exploit could cause Cisco IOS Software not to release allocated memory, causing a memory leak. A sustained attack may result in a device reload.
  
  Cisco has released software updates that address this vulnerability. There are no workarounds to mitigate this vulnerability.
  This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130925-ike
  

  Note: The September 25, 2013, Cisco IOS Software Security Advisory bundled publication includes eight Cisco Security Advisories. All advisories address vulnerabilities in Cisco IOS Software. 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 2013 bundled publication.

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

  http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep13.html

  
  

Affected Products

• 
  

  Vulnerable Products

  Although only IKEv1 packets can be used to trigger this vulnerability, devices that are running Cisco IOS Software or Cisco IOS XE Software are vulnerable when they are configured to use IKEv1 or IKEv2.
  
  Configuring IKEv2 on Cisco IOS Software or Cisco IOS XE Software automatically enables IKEv1.
  
  A number of features use IKEv1, including different types of VPNs such as the following:
  

  
  

  • LAN-to-LAN VPN
  • Remote access VPN (excluding SSLVPN)
  • Dynamic Multipoint VPN (DMVPN)
  • Group Domain of Interpretation (GDOI)

  
  The preferred method to determine whether a device has been configured for IKE is to issue the show ip sockets or show udp EXEC command. If the device has UDP port 500, UDP port 4500, or UDP port 848 open, it is processing IKE packets.
  

  
  In the following example, the device is processing IKE packets in UDP port 500 and UDP port 4500, using either IP version 4 (IPv4) or IP version 6 (IPv6):
  

  
  

  router# show udp 
  Proto        Remote      Port      Local       Port  In Out  Stat TTY OutputIF  
  17       --listen--          192.168.130.21    500   0   0 1001011   0   
  17(v6)   --listen--          UNKNOWN           500   0   0 1020011   0   
  17       --listen--          192.168.130.21   4500   0   0 1001011   0   
  17(v6)   --listen--          UNKNOWN          4500   0   0 1020011   0  
  !--- Output truncated 
  router#
  
  

  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

  Cisco IOS XR Software is not affected by this vulnerability.
  
  Cisco ASA 5500 Series Adaptive Security Appliance is not affected by this vulnerability.
  
  No other Cisco products are currently known to be affected by this vulnerability.

Details

• The IKE protocol is used in the IP Security (IPsec) protocol suite to negotiate cryptographic attributes that will be used to encrypt or authenticate the communication session. These attributes include cryptographic algorithm, mode, and shared keys. The result of IKE is a shared session secret that will be used to derive cryptographic keys.
  
  Cisco IOS Software or Cisco IOS XE Software support IKE for IPv4 and IPv6 communications. IKE communication can use any of the following UDP ports:
  

  
  

  • UDP port 500
  • UDP port 4500, Network Address Translation (NAT) Traversal (NAT-T)
  • UDP port 848, Group Domain of Interpretation (GDOI)

  A vulnerability in the Internet Key Exchange (IKE) protocol of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a memory leak that could lead to a device reload.
  
  The vulnerability is due to incorrect handling of malformed IKE packets by the affected software. An attacker could exploit this vulnerability by sending crafted IKE packets to a device configured with features that leverage IKE version 1 (IKEv1).
  
  Although IKEv1 is automatically enabled on a Cisco IOS Software and Cisco IOS XE Software when IKEv1 or IKE version 2 (IKEv2) is configured, the vulnerability can be triggered only by sending a malformed IKEv1 packet.
  
  In specific conditions, normal IKEv1 packets can also cause an affected release of Cisco IOS Software to leak memory.
  
  Only IKEv1 is affected by this vulnerability.
  
  An exploit could cause Cisco IOS Software not to release allocated memory, causing a memory leak. A sustained attack may result in a device reload.
  An attacker could exploit this vulnerability using either IPv4 or IPv6 on any of the listed UDP ports.
  
  

  How to Determine Whether the Vulnerability Has Been Exploited

  To determine whether the vulnerability has been exploited on an affected device, issue the show memory debug leaks summary command from the command-line interface.
  
  The following example shows the output of an affected Cisco IOS or Cisco IOS XE device where there are observed memory leaks in IKE FSM CONTEXT:

  
  

  Router#show memory debug leaks summary
  Adding blocks for GD...
  
                   I/O memory                 
  Alloc PC        Size     Blocks      Bytes    What
  
                   Processor memory                 
  Alloc PC        Size     Blocks      Bytes    What
  
  0x651A3D38 0000000092 0000000005 0000000460    IKE FSM CONTEXT
  0x651A3D38 0000000104 0000000002 0000000208    IKE FSM CONTEXT
  0x651A3D38 0000000112 0000000002 0000000224    IKE FSM CONTEXT
  0x651A3D38 0000000156 0000000002 0000000312    IKE FSM CONTEXT

  
  Note: The show memory debug leaks summary command may be CPU intensive and should be used with caution.
  
  This vulnerability is documented in Cisco bug ID CSCtx66011 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2013-5473.
  
  

Workarounds

• There are no workarounds for this vulnerability.
  
  The following identification mechanism exists for this vulnerability.
  

  Embedded Event Manager (EEM)

  A Cisco IOS Embedded Event Manager (EEM) policy that is based on Tool Command Language (Tcl) can be used on vulnerable Cisco IOS devices to identify and detect a memory leak that is caused by this vulnerability. The policy allows administrators to monitor the memory for the affected process on a Cisco IOS device. When Cisco IOS EEM detects potential exploitation of this vulnerability, the policy can trigger a response by sending an alert to the network administrator, who could then decide to implement an upgrade or reload the device to recover the lost memory at a suitable time. The example policy is based on a Tcl script that sends a syslog message when the memory keeps dropping and reaches EEM_IKE_BUFF_INCR_THRES and when the IKE buffers have dropped EEM_IKE_BUFF_INCR_THRES times. If IKE buffers are freed the counter starts counting from zero. After generating the memory leak syslog message the script re-initializes.
  The Tcl script is available for download in Cisco Beyond: Embedded Event Manager (EEM) Scripting Community.
  
  A sample device configuration follows:
  
  
  

  event manager environment EEM_MEM_LEAK_INTERVAL 20
  event manager environment EEM_MEM_LEAK_MAX_RUNTIME 5
  event manager environment EEM_IKE_BUFF_INCR_THRES 3
  event manager environment EEM_FREE_MEMORY_THRES 70
  event manager directory user policy "flash:/"
  event manager policy eem_ike_mem_leak.tcl

  
  

Fixed Software

• When considering software upgrades, customers are advised to consult the Cisco Security Advisories, Responses, and Notices 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 2013 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 2013 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 2013 Cisco IOS Software Security Advisory Bundled Publication
  12.2EX	Not vulnerable	Vulnerable; First fixed in Release 15.0SE
  12.2EY	Not vulnerable	Vulnerable; First fixed in Release 15.2S
  12.2EZ	Not vulnerable	Releases prior to 12.2(60)EZ2 are vulnerable; Releases 12.2(60)EZ2 and later are not vulnerable. First fixed in Release 15.0SE
  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.
  12.2IXG	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2IXH	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2MC	Not vulnerable	Vulnerable; First fixed in Release 15.1M
  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.
  12.2SB	Not vulnerable	12.2(33)SB15
  12.2SCA	Not vulnerable	Vulnerable; First fixed in Release 12.2SCH
  12.2SCB	Not vulnerable	Vulnerable; First fixed in Release 12.2SCH
  12.2SCC	Not vulnerable	Vulnerable; First fixed in Release 12.2SCH
  12.2SCD	Not vulnerable	Vulnerable; First fixed in Release 12.2SCH
  12.2SCE	Not vulnerable	Vulnerable; First fixed in Release 12.2SCH
  12.2SCF	Not vulnerable	Vulnerable; First fixed in Release 12.2SCH
  12.2SCG	Not vulnerable	Vulnerable; First fixed in Release 12.2SCH
  12.2SCH	Not vulnerable	12.2(33)SCH1
  12.2SE	Not vulnerable	12.2(55)SE8
  12.2SEG	Not vulnerable	Vulnerable; First fixed in Release 15.0SE
  12.2SG	Not vulnerable	12.2(53)SG10; available December 2013 *
  12.2SGA	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2SM	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2SQ	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2SRA	Not vulnerable	Vulnerable; First fixed in Release 12.2SRE
  12.2SRB	Not vulnerable	Vulnerable; First fixed in Release 12.2SRE
  12.2SRC	Not vulnerable	Vulnerable; First fixed in Release 12.2SRE
  12.2SRD	Not vulnerable	Vulnerable; First fixed in Release 12.2SRE
  12.2SRE	Not vulnerable	12.2(33)SRE9
  12.2STE	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2SV	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2SVD	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2SVE	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2SW	Not vulnerable	Vulnerable; First fixed in Release 15.1M
  12.2SXF	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2SXH	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2SXI	Not vulnerable	12.2(33)SXI12
  12.2SXJ	Not vulnerable	12.2(33)SXJ6
  12.2SY	Not vulnerable	Vulnerable; First fixed in Release 15.0SY
  12.2WO	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  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; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  12.2ZYA	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  Affected 12.3-Based Releases	First Fixed Release	First Fixed Release for All Advisories in the September 2013 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 2013 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 2013 Cisco IOS Software Security Advisory Bundled Publication
  There are no affected 15.0 based releases
  Affected 15.1-Based Releases	First Fixed Release	First Fixed Release for All Advisories in the September 2013 Cisco IOS Software Security Advisory Bundled Publication
  15.1EY	Not vulnerable	Vulnerable; First fixed in Release 15.2S
  15.1GC	Not vulnerable	Vulnerable; First fixed in Release 15.1M
  15.1M	15.1(4)M5	15.1(4)M7
  15.1MR	Releases up to and including 15.1(1)MR4 are not vulnerable.	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  15.1MRA	Not vulnerable	15.1(3)MRA2
  15.1S	Cisco IOS XE devices: Please see Cisco IOS XE Software Availability	15.1(3)S6 Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
  15.1SG	Cisco IOS XE devices: Please see Cisco IOS XE Software Availability	15.1(2)SG1 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; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  15.1SVD	Not vulnerable	Not vulnerable
  15.1SVE	Not vulnerable	Not vulnerable
  15.1SVF	Not vulnerable	Not vulnerable
  15.1SY	Not vulnerable	15.1(1)SY2; Available on 28-OCT-13 15.1(2)SY
  15.1T	Not vulnerable	Vulnerable; First fixed in Release 15.1M
  15.1XO	Not vulnerable	Not vulnerable
  Affected 15.2-Based Releases	First Fixed Release	First Fixed Release for All Advisories in the September 2013 Cisco IOS Software Security Advisory Bundled Publication
  15.2E	Not vulnerable	Not vulnerable
  15.2GC	15.2(3)GC1 15.2(4)GC	Vulnerable; migrate to any release in 15.4T
  15.2JA	Not vulnerable	15.2(4)JA1
  15.2JAX	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  15.2JB	Not vulnerable	15.2(2)JB2
  15.2JN	Not vulnerable	Not vulnerable
  15.2M	Not vulnerable	15.2(4)M4
  15.2S	15.2(4)S Cisco IOS XE devices: Please see Cisco IOS XE Software Availability	15.2(4)S4 Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
  15.2SA	Not vulnerable	15.2(2)SA
  15.2SNG	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  15.2SNH	Not vulnerable	Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
  15.2SNI	Not vulnerable	Vulnerable; First fixed in Release 15.3S
  15.2T	15.2(3)T3	15.2(3)T4
  Affected 15.3-Based Releases	First Fixed Release	First Fixed Release for All Advisories in the September 2013 Cisco IOS Software Security Advisory Bundled Publication
  There are no affected 15.3 based releases

  
  * Cisco Catalyst 4500 Series Switches with Cisco Catalyst 4500 Supervisor Engines 6-E or 6L-E can migrate to Cisco IOS Software Release 15.1SG.
  
  

  Cisco IOS XE Software

  For a mapping of Cisco IOS XE Software releases to Cisco IOS Software releases, refer to Cisco IOS XE 2 Release Notes, Cisco IOS XE 3S Release Notes, and Cisco IOS XE 3SG Release Notes.
  
  

  Cisco IOS XE Software Release	First Fixed Release	First Fixed Release for All Advisories in the September 2013 Cisco IOS Software Security Advisory Bundled Publication
  2.1.x	Not vulnerable	Vulnerable; migrate to 3.4.6S or later.
  2.2.x	Not vulnerable	Vulnerable; migrate to 3.4.6S or later.
  2.3.x	Not vulnerable	Vulnerable; migrate to 3.4.6S or later.
  2.4.x	Not vulnerable	Vulnerable; migrate to 3.4.6S or later.
  2.5.x	Not vulnerable	Vulnerable; migrate to 3.4.6S or later.
  2.6.x	Not vulnerable	Vulnerable; migrate to 3.4.6S or later.
  3.1.xS	Not vulnerable	Vulnerable; migrate to 3.4.6S or later.
  3.1.xSG	Not vulnerable	Vulnerable; migrate to 3.4.1SG or later.
  3.2.xS	Not vulnerable	Vulnerable; migrate to 3.4.6S or later.
  3.2xSE	Not vulnerable	3.2.3SE
  3.2.xSG	Not vulnerable	Vulnerable; migrate to 3.4.1SG or later.
  3.2.xXO	Not vulnerable	Vulnerable; migrate to 3.3.0XO or later.
  3.2.xSQ	Not vulnerable	Vulnerable; migrate to 3.3.0SQ or later.
  3.3.xS	Not vulnerable	Vulnerable; migrate to 3.4.6S or later.
  3.3xSG	Not vulnerable	Vulnerable; migrate to 3.4.1SG or later.
  3.3xXO	Not vulnerable	Not vulnerable
  3.3xSQ	Not vulnerable	Not vulnerable
  3.4.xS	Only releases 3.4.2S through 3.4.5S are vulnerable.	3.4.6S
  3.4.xSG	Not vulnerable	3.4.1SG*
  3.5.xE	Not vulnerable	Not vulnerable
  3.5.xS	Not vulnerable	Vulnerable; migrate to 3.7.4S or later.
  3.6.xS	3.6.1S	Vulnerable; migrate to 3.7.4S or later.
  3.7.xS	Not vulnerable	3.7.4S
  3.8.xS	Not vulnerable	Vulnerable; migrate to 3.9.2S or later.
  3.9.xS	Not vulnerable	3.9.2S
  3.10.xS	Not vulnerable	Not vulnerable

  
  * Cisco Catalyst 4500 Series Switches with Cisco Catalyst 4500 Supervisor Engines 7-E and 7L-E and Cisco Catalyst 4500-X Series Switches can migrate to Cisco IOS XE Software Release 3.4SG.
  
  

  Cisco IOS XR Software

  Cisco IOS XR Software is not affected by any of the vulnerabilities that are disclosed in the September 2013 Cisco IOS Software Security Advisory Bundled Publication.
  
  

  
  

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 discovered during resolution of a support case.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130925-ike

Revision History

• Revision 1.0

  2013-September-25

  Initial public release

  Show Less