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Cisco Security Advisory

Cisco Unified Presence and Jabber Extensible Communications Platform Stream Header Denial of Service Vulnerability

Advisory ID: cisco-sa-20120912-cupxcp

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120912-cupxcp

Revision 1.0

For Public Release 2012 September 12 16:00  UTC (GMT)

Related Resources:

View related Applied Mitigation BulletinView related Alert

Summary

A denial of service (DoS) vulnerability exists in Cisco Unified Presence and Jabber Extensible Communications Platform (Jabber XCP). An unauthenticated, remote attacker could exploit this vulnerability by sending a specially crafted Extensible Messaging and Presence Protocol (XMPP) stream header to an affected server. Successful exploitation of this vulnerability could cause the Connection Manager process to crash.  Repeated exploitation could result in a sustained DoS condition.

There are no workarounds available to mitigate exploitation of this vulnerability.

Cisco has released free software updates that address this vulnerability.  This advisory is available at the following link:
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120912-cupxcp

Affected Products


Vulnerable Products

The following versions of Cisco Unified Presence and Jabber Extensible Communications Platform (Jabber XCP) are affected by the vulnerability in this advisory. JabberNow appliances are also affected if they are running a vulnerable version of Jabber XCP software.

Cisco Unified Presence

All versions of Cisco Unified Presence prior to 8.6(3) are affected by the vulnerability in this advisory.

Jabber XCP and JabberNow Appliances

All versions of Jabber XCP software prior to 5.3 are affected by the vulnerability in this advisory.

Determining Cisco Unified Presence Software Versions

To determine the running version of Cisco Unified Presence software, issue the show version active command from the command line interface.

The following example shows Cisco Unified Presence software version 8.6.0:
admin: show version active
Active Master Version: 8.6.0.97041-43

 Determining Jabber XCP Software Versions

To determine the running version of Jabber XCP software, find the JABBER_VERSION in the [JABBER_HOME]/var/cache/xcp_vars.sh file.

The following example shows Jabber XCP software version 5.8.1.17421:
$ cat [JABBER_HOME]/var/cache/xcp_var.sh | grep JABBER_VERSION JABBER_VERSION=5.8.1.17421

Products Confirmed Not Vulnerable

No other Cisco products are currently known to be affected by this vulnerability.

Details

Cisco Unified Presence and Jabber XCP provide an open and extensible platform that facilitates the secure exchange of availability and instant messaging (IM) information.

Cisco Unified Presence contains a vulnerability that could allow an unauthenticated, remote attacker to cause a DoS condition.

Jabber Extensible Communications Platform, including JabberNow Appliance, contains a vulnerability that could allow an unauthenticated, remote attacker to cause a DoS condition.

XMPP clients initiate communication with an XMPP server by sending a stream header using IP version 4 (IPv4) or IP version 6 (IPv6). The vulnerability is due to the incorrect handling of stream headers. An attacker could exploit this vulnerability by sending a specially crafted XMPP stream header to an affected system. A successful exploit could cause the Connection Manager processes to terminate, resulting in dropped connections for existing clients and preventing new clients from connecting. The Connection Manager processes will restart automatically. However, repeated exploitation could create a sustained DoS condition.

More information about XMPP stream headers is available in RFC 6120.

This vulnerability is documented in Cisco bug ID CSCtu32832 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2012-3935.

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

CSCtu32832 - CUP and Jabber XCP Stream Header Denial of Service Vulnerability

Calculate the environmental score of CSCtu32832

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 - 6.1

Exploitability

Remediation Level

Report Confidence

Proof-of-Concept

Official-Fix

Confirmed


Impact

Successful exploitation of this vulnerability could cause Connection Manager processes to terminate, resulting in dropped connections for existing clients and preventing new clients from connecting. The Connection Manager processes will restart automatically. However, repeated exploitation could result in a sustained DoS condition for all users of the server.

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 Unified Presence Software Version

First Fixed Release

All versions prior to 8.6(3)

Upgrade to 8.6(3) or higher



Jabber XCP Software Version, Including JabberNow Appliances

First Fixed Release

All versions prior to 5.3

Upgrade to 5.3 or higher


Workarounds

There are no available workarounds to mitigate this vulnerability.

Additional mitigations that can be deployed on Cisco devices within the network are available in the Cisco Applied Intelligence companion document for this Advisory: http://tools.cisco.com/security/center/viewAMBAlert.x?alertId=26732

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.

The vulnerability described in this advisory was found during internal testing.

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-20120912-cupxcp

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-12 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.


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