Cisco Security Advisory
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A vulnerability in the implementation of the IP version 6 (IPv6) protocol stack in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause I/O memory depletion on an affected device that has IPv6 enabled. The vulnerability is triggered when an affected device processes a malformed IPv6 packet.
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-20140326-ipv6
Note: The March 26, 2014, Cisco IOS Software Security Advisory bundled publication includes six 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 March 2014 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_mar14.html
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This vulnerability affects Cisco devices running an affected Cisco IOS Software or Cisco IOS XE Software release and have IPv6 enabled. IPv6 is not enabled by default in Cisco IOS Software and Cisco IOS XE Software.
Vulnerable Products
A Cisco device running an affected version of Cisco IOS Software or Cisco IOS XE Software release and has IPv6 enabled will show interfaces with assigned IPv6 addresses when the show ipv6 interface brief command is issued.
The show ipv6 interface brief command will produce an error message if the running version of Cisco IOS Software or Cisco IOS XE Software release does not support IPv6, or will not show any interfaces with IPv6 addresses if IPv6 is disabled. The system is not vulnerable in either scenario.
The following example shows the output from the show ipv6 interface brief command issued on a device running Cisco IOS Software enabled for IPv6:
The IPv6 protocol is enabled if the interface configuration command ipv6 address <IPv6 address> or ipv6 enable is present in the configuration; however, both may be present. The following examples shows a vulnerable configuration with both present:router>show ipv6 interface brief FastEthernet0/0 [up/up] FE80::222:90FF:FEB0:1098 2001:DB8:2:93::3 200A:1::1 FastEthernet0/1 [up/up] FE80::222:90FF:FEB0:1099 2001:DB8:2:94::1 Serial0/0/0 [down/down] unassigned Serial0/0/0.4 [down/down] unassigned Serial0/0/0.5 [down/down] unassigned Serial0/0/0.6 [down/down] unassigned
A device running Cisco IOS Software or Cisco IOS XE Software with IPv6 enabled on a physical or logical interface is vulnerable even if ipv6 unicast-routing is globally disabled (that is, the device is not routing IPv6 packets).interface FastEthernet0/1 ipv6 address 2001:0DB8:C18:1::/64 eui-64 ! interface FastEthernet0/2 ipv6 enable
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 15.2(4)M5 with an installed image name of C3900-UNIVERSALK9-M:
Router> show version
Cisco IOS Software, C3900 Software (C3900-UNIVERSALK9-M), 15.2(4)M5, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2013 by Cisco Systems, Inc.
Compiled Fri 13-Sep-13 16:44 by prod_rel_team!--- output truncatedAdditional information about Cisco IOS Software release naming conventions is available in White Paper: Cisco IOS and NX-OS Software Reference Guide.
Products Confirmed Not Vulnerable
The following products are not affected by this vulnerability:- Cisco IOS XR Software
- Cisco NX-OS Software
- Cisco ASA Software
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Designed by the Internet Engineering Task Force (IETF), IPv6 is intended to replace the current IP version (IPv4).
A vulnerability in the implementation of the IPv6 protocol stack in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause I/O memory depletion on the affected device.
The vulnerability is due to incorrect processing of crafted IPv6 packets. An attacker could exploit this vulnerability by sending specially crafted IPv6 packets to the affected device. An exploit could allow the attacker to trigger I/O memory depletion, causing device instability and could cause a device to reload.
This vulnerability has been documented in Cisco bug ID CSCui59540 (registered customers only), and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2014-2113
The vulnerability is triggered when an affected device processes a malformed IPv6 packet. Transit IPv6 traffic will not trigger this vulnerability.
Identification of potentially hitting this vulnerability would be via small amounts of I/O memory being available as shown in the following example via the show memory summary CLI command:
Memory will be held by the Pool Manager process as shown in the following example via the show memory debug leaks chunks command:Router#show memory summary
Head Total(b) Used(b) Free(b) Lowest(b) Largest(b)
Processor 128C7B50 759290240 249009244 510280996 504250376 510241908
I/O 3C400000 62914560 62912692 1868 1868 236
A reload of the device is required to release the memory. Disabling IPv6 by removing the IPv6 configuration will not release the memory.Router#show memory debug leaks chunks
Adding blocks for GD...
I/O memory
Address Size Alloc_pc PID Alloc-Proc Name
Chunk Elements:
AllocPC Address Size Parent Name
Processor memory
Address Size Alloc_pc PID Alloc-Proc Name
1020A20 1244 430FAC8 7 Pool Manager *Packet Header*
102226C 1244 430FAC8 7 Pool Manager *Packet Header*
1022C24 1244 430FAC8 7 Pool Manager *Packet Header*
1023100 1244 430FAC8 7 Pool Manager *Packet Header*
10235DC 1244 430FAC8 7 Pool Manager *Packet Header*
1023AB8 1244 430FAC8 7 Pool Manager *Packet Header*
102494C 1244 430FAC8 7 Pool Manager *Packet Header*
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If IPv6 configuration is required, there are no workarounds for this vulnerability.
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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.
In February 2014, Cisco announced details of an industry-wide issue with memory components manufactured by a single supplier between 2005 and 2010. Although the majority of Cisco products that use these components are experiencing field failure rates below expected levels, a device reload or power cycle could expose component failures. While there are no known security implications associated with this issue, a subset of the affected products may experience a memory component failure during the software upgrade process. Cisco recommends customers review the related information and product-specific field notices at www.cisco.com/go/memory before making upgrade decisions. Each Field Notice indicates whether the product could experience the memory component failure during a software upgrade.
Cisco IOS Software
The Cisco IOS Software Checker is the quickest method to determine exposure to vulnerabilities in Cisco IOS Software. The tool allows customers to quickly identify Cisco Security Advisories that impact specific Cisco IOS Software releases. Users can initiate a search by selecting releases from the drop-down menu or uploading a file from their local system. The tool is also capable of parsing show version command output. Results can be customized by searching against all previously published Cisco Security Advisories, a specific publication, or all the advisories in the March 2014 Bundled Publication.
Customers can also use the Cisco IOS Software tables below to determine their exposure. Each row corresponds to a Cisco IOS Software release; if a particular release is vulnerable, the earliest releases that contain the fix are listed in the second column. The third column lists the earliest possible releases that correct all vulnerabilities in this Cisco IOS Software Security Advisory bundled publication.
Expand to View Detailed Fixed Software Information
Cisco IOS XE Software
Cisco IOS XE Software Release First Fixed Release First Fixed Release for All Advisories in the March 2014 Cisco IOS Software Security Advisory Bundled Publication 2.1.x Not vulnerable Not vulnerable 2.2.x Not vulnerable Not vulnerable 2.3.x Not vulnerable Not vulnerable 2.4.x Not vulnerable Not vulnerable 2.5.x Not vulnerable Not vulnerable 2.6.x Not vulnerable Not vulnerable 3.1.xS Not vulnerable Not vulnerable 3.1.xSG Not vulnerable Not vulnerable 3.2.xS Not vulnerable Vulnerable; migrate to 3.7.5S or later. 3.2xSE Not vulnerable Not vulnerable 3.2.xSG Not vulnerable Not vulnerable 3.2.xXO Not vulnerable Not vulnerable 3.2.xSQ Not vulnerable Not vulnerable 3.3.xS Not vulnerable Vulnerable; migrate to 3.7.5S or later. 3.3.xSE Not vulnerable Not vulnerable. 3.3xSG Not vulnerable Vulnerable; migrate to 3.5.2E. 3.3xXO Vulnerable; migrate to 3.6.0E (available May 2014). Vulnerable; migrate to 3.6.0E (available May 2014). 3.3xSQ Not vulnerable Not vulnerable 3.4.xS Not vulnerable Vulnerable; migrate to 3.7.5S or later. 3.4.xSG Not vulnerable Vulnerable; migrate to 3.5.2E. 3.5.xS Not vulnerable Vulnerable; migrate to 3.7.5S or later. 3.5.xE 3.5.2E 3.5.2E 3.6.xS Not vulnerable Vulnerable; migrate to 3.7.5S or later. 3.6.xE Not vulnerable 3.6.0E (available May 2014) 3.7.xS 3.7.5S 3.7.5S 3.8.xS Vulnerable; migrate to 3.10.2S or later. Vulnerable; migrate to 3.10.2S or later. 3.9.xS Vulnerable; migrate to 3.10.2S or later. Vulnerable; migrate to 3.10.2S or later. 3.10.xS 3.10.2S 3.10.2S 3.11.xS Not vulnerable Not vulnerable Cisco IOS XR Software
Cisco IOS XR Software is not affected by any of the vulnerabilities that are disclosed in the March 2014 Cisco IOS Software Security Advisory Bundled Publication.
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The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
This vulnerability was discovered by Cisco during internal testing.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Show LessRevision 1.0 2014-March-26 Initial public release.
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