A vulnerability in the DHCP version 6 (DHCPv6) server implementation of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper parsing of malformed DHCPv6 packets. An attacker could exploit this vulnerability by sending malformed DHCPv6 packets to be processed by an affected device. An exploit could allow the attacker to cause a memory leak and eventual reload of an affected device. Cisco has released software updates that address this vulnerability. This advisory is available at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20140924-dhcpv6 Note: The September 24, 2014, Cisco IOS Software Security Advisory bundled publication includes six Cisco Security Advisories. All advisories address vulnerabilities in Cisco IOS Software. 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_sep14.html
http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep14.html
The following example shows a Cisco IOS device that is affected by this vulnerability. The device is vulnerable because the DHCPv6 server feature is applied to the FastEthernet0/0 interface and DHCPv6 server pool DHCPv6-stateful is used:Router#show ipv6 dhcp interface Router#
The following example shows a Cisco IOS device that is affected by this vulnerability. The device is vulnerable because the DHCPv6 server feature is applied to the FastEthernet0/0 and FastEthernet0/1 interfaces:Router#show ipv6 dhcp interface FastEthernet0/0 is in server mode Using pool: DHCPv6-stateful Preference value: 0 Hint from client: ignored Rapid-Commit: disabled Router#
Router#show ipv6 dhcp interface | include server FastEthernet0/0 is in server mode FastEthernet0/1 is in server mode 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 15.2(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 truncated
Additional information about Cisco IOS Software release naming conventions is available in White Paper: Cisco IOS and NX-OS Software Reference Guide.
Cisco has provided a tool to help customers determine their exposure to vulnerabilities in Cisco IOS Software. The Cisco IOS Software Checker allows customers to perform the following tasks:
The tool will identify any Cisco Security Advisories that impact a queried software release and the earliest release that corrects all vulnerabilities in each Cisco Security Advisory ("First Fixed"). If applicable, the tool will also return the earliest possible release that corrects all vulnerabilities in all displayed advisories ("Combined First Fixed"). Please visit the Cisco IOS Software Checker or simply enter a Cisco IOS Software release in the following field to determine whether it is affected by any of the advisories in this bundled publication.
(Example entry: 15.1(4)M2)
Cisco IOS XE Software Release |
First Fixed Release |
First Fixed Release for
All Advisories in the September 2014 Cisco IOS Software Security Advisory Bundled Publication |
---|---|---|
2.1.x | Not vulnerable | Vulnerable; migrate to 3.7.6S or later. |
2.2.x | Not vulnerable | Vulnerable; migrate to 3.7.6S or later. |
2.3.x | Not vulnerable | Vulnerable; migrate to 3.7.6S or later. |
2.4.x | Not vulnerable | Vulnerable; migrate to 3.7.6S or later. |
2.5.x | Not vulnerable | Vulnerable; migrate to 3.7.6S or later. |
2.6.x | Not vulnerable | Vulnerable; migrate to 3.7.6S or later. |
3.1.xS | Not vulnerable | Vulnerable; migrate to 3.7.6S or later. |
3.1.xSG | Not vulnerable | Not vulnerable |
3.2.xS | Not vulnerable | Vulnerable; migrate to 3.7.6S or later. |
3.2.xSE | Not vulnerable | Vulnerable; migrate to 3.3.2SE |
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 3.7.6S or later. |
3.3.xSE | Not vulnerable | 3.3.2SE |
3.3.xSG | Not vulnerable | Vulnerable; migrate to 3.4.4SG or later. |
3.3.xXO | Not vulnerable | 3.3.1XO |
3.3.xSQ | Not vulnerable | Not vulnerable |
3.4.xS | Vulnerable; migrate to 3.7.6S or later. | Vulnerable; migrate to 3.7.6S or later. |
3.4.xSG | Not vulnerable | 3.4.4SG |
3.4.xSQ | Not vulnerable | Not vulnerable |
3.5.xE | Not vulnerable | 3.5.2E |
3.5.xS | Vulnerable; migrate to 3.7.4S or later. | Vulnerable; migrate to 3.7.6S or later. |
3.6.xE | Not vulnerable | Not vulnerable |
3.6.xS | Vulnerable; migrate to 3.7.4S or later | Vulnerable; migrate to 3.7.6S or later. |
3.7.xE | Not vulnerable | Not vulnerable |
3.7.xS | 3.7.6S | Vulnerable; migrate to 3.7.6S or later. |
3.8.xS | Vulnerable; migrate to 3.10.4S or later. | Vulnerable; migrate to 3.10.4S or later. |
3.9.xS | Vulnerable; migrate to 3.10.4S or later. | Vulnerable; migrate to 3.10.4S or later. |
3.10.xS | 3.10.4S | 3.10.4S |
3.11.xS | Vulnerable; migrate to 3.12S or later. | Vulnerable; migrate to 3.12S or later. |
3.12.xS | Not vulnerable | Not vulnerable |
3.13.xS | Not vulnerable | Not vulnerable |
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.
Revision 1.0 | 2014-September-24 | Initial public release. |
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.
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