Cisco Security Advisory

Contents

Summary
Affected Products
Details
Vulnerability Scoring Details
Impact
Software Versions and Fixes
Workarounds
Obtaining Fixed Software
Exploitation and Public Announcements
Status of This Notice: Final
Distribution
Revision History
Cisco Security Procedures

Vulnerable Products

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 

Products Confirmed Not Vulnerable

A vulnerability exists in the Smart Install feature of Cisco IOS Software that could allow an unauthenticated, remote attacker to cause a reload of an affected device. Smart Install uses a Cisco proprietary protocol that runs over TCP port 4786. To exploit this vulnerability, an attacker needs to establish a TCP session on port 4786 of an affected device that has the Smart Install feature enabled, and then send a malformed Smart Install message.

Cisco has scored the vulnerability in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this security advisory is in accordance with CVSS version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability severity and helps organizations determine the urgency and priority of a response.

Cisco has provided a base and temporal score. Customers can also compute environmental scores that help determine the impact of the vulnerability in their own networks.

Cisco has provided additional information regarding CVSS at the following link:

http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html

Cisco has also provided a CVSS calculator to compute the environmental impact for individual networks at the following link:

http://intellishield.cisco.com/security/alertmanager/cvss

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.

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 March 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 Intelligence Operations (SIO) portal at http://tools.cisco.com/security/center/selectIOSVersion.x

* Cisco Catalyst 3550 Series Switches support the Internet Key Exchange (IKE) feature and are vulnerable to Cisco bug ID CSCts38429 when the devices are running Layer 3 images; however, this product reached the End of Software Maintenance milestone.  Cisco 3550 Series SMI Switches that are running Layer 2 images do not support IKE and are not vulnerable.  No other Cisco devices that run 12.2SE-based software are vulnerable.

Cisco IOS XE Software

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

Cisco IOS XR Software

Cisco IOS XR Software is not affected by any of the vulnerabilities disclosed in the March 2012 Cisco IOS Software Security Advisory Bundled Publication.

In some versions of Cisco IOS Software, the Smart Install feature can be disabled with the global configuration command no vstack. In versions of Cisco IOS Software where this command is available, the vulnerability can be mitigated by disabling the Smart Install feature if it is not needed.

Note: The no vstack global configuration command to disable Smart Install was introduced with the fix for Cisco bug CSCtj75729 ("Ability to shut Smart Install default service on TCP port 4786"). If a Cisco IOS Software release supports the Smart Install feature but the no vstack command does not exist, the release does not contain the fix for Cisco bug CSCtj75729.

In versions of Cisco IOS Software that support only the Smart Install director functionality, Smart Install can be disabled with the no vstack basic global configuration command. This command also mitigates the vulnerability in cases where disabling Smart Install is operationally feasible.

If the Smart Install feature cannot be disabled because of operational constraints or because the no vstack command is not available, there are no workarounds. In this case, the only mitigation is to prevent TCP connections from untrusted sources to port 4786 on affected devices. Administrators can use the following mitigations on affected devices:

• Interface access control lists (ACLs)
• Control Plane Policing (CoPP; not available on all Cisco IOS Software releases)

Administrators can use the following mitigations on other devices in the network:

• Infrastructure access control lists (iACLs)
• VLAN access control lists (VACLs)

For information about additional mitigations that can be deployed on Cisco devices in the network, including iACLs and VACLs, refer to the Cisco Applied Mitigation Bulletin (AMB) companion document for this advisory, which is available at the following location: http://tools.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20120328-smartinstall.

Cisco has released free software updates that address the vulnerability described in this advisory. Prior to deploying software, customers are advised to consult their maintenance providers or check the software for feature set compatibility and known issues that are specific to their environments.

Customers may only install and expect support for feature sets they have purchased. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license at http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html, or as set forth 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 Using Third-Party Support Organizations

Customers Without Service Contracts

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 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.

This advisory is posted on Cisco Security Intelligence Operations at the following link

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120328-smartinstall

Additionally, a text version of this advisory is clear signed with the Cisco PSIRT PGP key and circulated among the following e-mail addresses:

• cust-security-announce@cisco.com
• first-bulletins@lists.first.org
• bugtraq@securityfocus.com
• vulnwatch@vulnwatch.org
• cisco@spot.colorado.edu
• cisco-nsp@puck.nether.net
• full-disclosure@lists.grok.org.uk

Future updates of this advisory, if any, will reside on Cisco.com but may not be announced on mailing lists. Users can monitor this advisory's URL for any updates.