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Cisco Catalyst 4500E Series Switch with Cisco Catalyst Supervisor Engine 7L-E Denial of Service Vulnerability

Advisory ID: cisco-sa-20120926-ecc

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120926-ecc

Revision 1.0

For Public Release 2012 September 26 16:00  UTC (GMT)


Summary

The Catalyst 4500E series switch with Supervisor Engine 7L-E contains a denial of service (DoS) vulnerability when processing specially crafted packets that can cause a reload of the device.

Cisco has released free software updates that address this vulnerability.

Workarounds that mitigate this vulnerability are not available.

This advisory is available at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120926-ecc

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

This vulnerability affects only the Catalyst 4500E series switch with Supervisor Engine 7L-E running Cisco IOS XE Software Release 03.02.00.XO.15.0(2)XO.  The device is vulnerable when running an affected version of Cisco IOS XE Software, regardless of the configuration of the device

To identify the hardware type log into the device and issue the show module Cisco IOS XE Software CLI command. The following example shows a Catalyst 4500-E Series with a Catalyst Supervisor Engine 7L-E installed:
switch#show module
Chassis Type : WS-C4507R+E

Power consumed by backplane : 40 Watts

Mod Ports Card Type                              Model              Serial No.
---+-----+--------------------------------------+------------------+-----------
 4     6  Sup 7L-E 10GE (SFP+), 1000BaseX (SFP)  WS-X45-SUP7L-E     CAT1532L4ZA
 5    48  10/100/1000BaseT (RJ45)                WS-X4448-GB-RJ45   JAB023456A3
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 Catalyst 4500E series switch with Supervisor Engine 7L-E that is running Cisco IOS XE Software Release 03.02.00.XO.15.0(2)XO with an installed image name of cat4500e-universal.SPA:
Catalyst_4500#show version
Cisco IOS Software, IOS-XE Software, Catalyst 4500 L3 Switch Software (cat4500e-UNIVERSAL-M), Version 03.02.00.XO RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2011 by Cisco Systems, Inc.
Compiled Thu 22-Sep-11 19:53 by prod_rel_team


<--- section removed for brevity ---> 

System returned to ROM by reload
System image file is "bootflash:/cat4500e-universal.SPA.03.02.00.XO.150-2.XO.bin"
Last reload reason: Reload command


License Information for 'WS-X45-SUP7L-E'
    License Level: lanbase   Type: Default. No valid license found.
    Next reboot license Level: lanbase

     <--- section removed for brevity --->
Additional information about Cisco IOS Software release naming conventions is available in White Paper: Cisco IOS and NX-OS Software Reference Guide.

Vulnerable Products

The following products are affected by this vulnerability, when running Cisco IOS XE Software Release 03.02.00.XO.15.0(2)XO:
  • Catalyst 4500E series switch with Supervisor Engine 7L-E

Products Confirmed Not Vulnerable

The following products are not affected by this vulnerability:
  • Cisco Catalyst Supervisor Engine II
  • Cisco Catalyst Supervisor Engine IV
  • Cisco Catalyst Supervisor Engine V
  • Cisco Catalyst Supervisor Engine 6-E and 6-LE
  • Cisco Catalyst Supervisor Engine 7-E
  • Cisco Catalyst 4500-X Series Switches
  • Cisco Catalyst 4900 Series Switches
  • Cisco ME 4924-10GE Ethernet Aggregation Switch
No other Cisco products are currently known to be affected by this vulnerability.

Details

Cisco Catalyst 4500E series switches with Supervisor Engine 7L-E contain a denial of service (DoS) vulnerability that could allow an unauthenticated, remote attacker to cause the device supervisor card to reload.

The vulnerability is due to improper processing of malformed network packets. An unauthenticated, remote attacker could exploit this vulnerability by sending specially crafted packets to or through the affected device. An exploit could allow the attacker to reload the affected device supervisor card, resulting in a DoS condition.
When the specially crafted packets are received the device will indicate an error message about an uncorrected error-correcting code (ECC) failure.  The following is an example of this error message:

%C4K_SWITCHINGENGINEMAN-4-VFEL2INTERRUPT: (Suppressed 9 times)VFE L2 sptMemory interrupt. valid: 1 addr: 0x0 data: 0x0 uncorrected ecc: 0
IF 100 of these packets have been received in a period of less than 72 hours, the device will reload.

There are also packets that would cause a similar error message but result in a corrected ECC error message.  These are informational and do not have an impact on the device itself.  The following is an example of this error message:

%C4K_SWITCHINGENGINEMAN-4-VFEL2INTERRUPT: VFE L2 sptMemory interrupt. valid: 1 addr: 0x0 data: 0x0 corrected ecc: 2
  
The device is vulnerable when running Cisco IOS XE Software Release 03.02.00.XO.15.0(2)XO, regardless of the configuration of the device.

 This vulnerability has been documented in Cisco Bug ID CSCty88456 (registered customers only) and has been assigned the Common Vulnerabilities and Exposures (CVE) ID CVE-2012-4622.


Vulnerability Scoring Details

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



CSCty88456
 - Catalyst 4500E series switch with Supervisor Engine 7L-E Denial of Service Vulnerability 

Calculate the environmental score of CSCty88456

CVSS Base Score - 7.8

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Low

None

None

None

Complete

CVSS Temporal Score - 6.4

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed


Impact

Successful exploitation of the vulnerability may cause the supervisor card on the affected device to reload.  Continued exploitation will result in a sustained denial of service attack.

Software Versions and Fixes

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

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

Cisco IOS XE Software

This vulnerability affects Cisco IOS XE Software Release 03.02.00.XO.15.0(2)XO only.

Devices running the affected Cisco IOS XE Software Release should migrate to release 3.3.0.SG or later.

Cisco IOS XE Software Release First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
2.1.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
2.2.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
2.3.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
2.4.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
2.5.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
2.6.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
3.1.xS Not vulnerable 3.1.4S
3.1.xSG Not vulnerable Vulnerable; migrate to 3.2.5SG or later.
3.2.xS Not vulnerable Vulnerable; migrate to 3.6.0S or later.
3.2.xSG Not vulnerable 3.2.5SG
3.2.xXO Vulnerable; migrate to 3.3.0SG or later. Vulnerable; migrate to 3.3.1SG or later.
3.3.xS Not vulnerable Vulnerable; migrate to 3.6.0S or later.
3.3.x.SG Not vulnerable 3.3.1SG
3.4.xS Not vulnerable Vulnerable; migrate to 3.6.0S or later.
3.5.xS Not vulnerable Vulnerable; migrate to 3.6.0S or later.
3.6.xS Not vulnerable Not vulnerable
3.7.xS Not vulnerable Not vulnerable

 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 XR Software

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

Workarounds

The are no workarounds for this vulnerability. The use of port access control lists (PACL) and VLAN access control lists (VACL) does not mitigate this vulnerability.

Obtaining Fixed Software

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.

Customers with Service Contracts

Customers with contracts should obtain upgraded software through their regular update channels. For most customers, upgrades should be obtained through the Software Navigator on Cisco.com at http://www.cisco.com/cisco/software/navigator.html.

Customers using Third Party Support Organizations

Customers with Cisco products that are provided or maintained through prior or existing agreements with third-party support organizations, such as Cisco Partners, authorized resellers, or service providers, should contact that organization for assistance with the appropriate course of action.

The effectiveness of any workaround or fix depends on specific customer situations, such as product mix, network topology, traffic behavior, and organizational mission. Because of the variety of affected products and releases, customers should consult their service providers or support organizations to ensure that any applied workaround or fix is the most appropriate in the intended network before it is deployed.

Customers without Service Contracts

Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC):

  • +1 800 553 2447 (toll free from within North America)
  • +1 408 526 7209 (toll call from anywhere in the world)
  • e-mail: tac@cisco.com

Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade. Customers without service contracts should request free upgrades through the TAC.

Refer to Cisco Worldwide Contacts at http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, instructions, and e-mail addresses for support in various languages.

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 when handling customer service requests.

Status of this Notice: Final

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.


Distribution

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

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120926-ecc

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.


Revision History

Revision 1.0 2012-September-26 Initial public release

Cisco Security Procedures

Complete information about reporting security vulnerabilities in Cisco products, obtaining assistance with security incidents, and registering to receive security information from Cisco is available on Cisco.com at http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html. This web page includes instructions for press inquiries regarding Cisco Security Advisories. All Cisco Security Advisories are available at http://www.cisco.com/go/psirt.