Cisco Unified Communications Manager IM and Presence Service SIP Packet Processing Denial of Service Vulnerability

Summary

• A vulnerability in Session Initiation Protocol (SIP) processing functions of the Cisco Unified Communications Manager Instant Messaging (IM) and Presence Service could allow an unauthenticated, remote attacker to cause the Cisco SIP Proxy Daemon (sipd) process to restart unexpectedly, resulting in a denial of service (DoS) condition on a targeted system.
  
  The vulnerability is due to improper input validation of SIP packet headers. An attacker could exploit this vulnerability by sending a crafted SIP packet to a targeted system. A successful exploit could allow the attacker to cause the sipd process to restart unexpectedly, resulting in a DoS condition on the system. If the sipd process restarts repeatedly, a successful exploit could also result in a sustained DoS condition and cause high disk utilization due to a large number of sipd core files being written to disk, which could exacerbate the DoS condition.
  
  Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
  
  This advisory is available at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160803-ucm

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco Unified Communications Manager IM and Presence Service versions 9.1(1) SU6, 9.1(1) SU6a, 9.1(1) SU7, 10.5(2) SU2, 10.5(2) SU2a, 11.0(1) SU1, and 11.5(1).
  
  To determine whether a vulnerable version of the Cisco Unified Communications Manager IM and Presence Service is running on a device, administrators can use the show version active command in the command-line interface (CLI) for the device.
  
  The following example shows the output from a device that is running version 11.5(1) of the service:

  admin: show version active
  Active Master Version: 11.5.1.10000-4
  Active Version Installed Software Options:
  No Installed Software Options Found.

  Products Confirmed Not Vulnerable

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

Indicators of Compromise

• Exploitation of this vulnerability could cause the sipd process to restart and generate an sipd core file. If the vulnerability is exploited repeatedly on a device, a large number of sipd core file could be generated and written to disk, causing high disk utilization.
  
  Contact the Cisco Technical Assistance Center (TAC) to review the sipd core files and system log files to determine whether the device has been compromised by exploitation of this vulnerability.
  
  Administrators can display all active core files on a disk by using the utils core active list command in the CLI for the device. The names of sipd core files will adhere to the following syntax: core.xxxx.sipd.xxxxx
  
  To determine whether sipd core files are using a high percentage of disk space, administrators can use the show diskusage common sort command in the CLI. To delete sipd core files from a disk, administrators can use the following command in the CLI:

  file delete activelog /core/core.*.sipd.* noconfirm

Workarounds

• There are no workarounds that address this vulnerability.

Fixed Software

• Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
  http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html
  
  Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
  
  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 upgrade 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.
  
  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):
  http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html
  
  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.
  
  Fixed Releases
  
  Customers are advised to install an appropriate fixed release as indicated in this section.
  
  This vulnerability has been fixed in the following releases:

  • Version 11.5(1) SU1 for service version 11.5(1)
  • Cisco Optional Package ciscocm.cup-psirt-sipd-1151-v1.1.cop.sgn for service versions 11.5(1)
  • Cisco Optional Package ciscocm.cup-psirt-sipd-1101-v1.1.cop.sgn for service versions 11.0(1)
  • Cisco Optional Package ciscocm.cup-psirt-sipd-1052-v1.1.cop.sgn for service versions 10.5(2)
  • Cisco Optional Package ciscocm.cup-psirt-sipd-911SU-v1.1.cop.sgn for service versions 9.1(1)

  Customers can download software for the Cisco Unified Communications Manager IM and Presence Service from the Software Center on Cisco.com by navigating to Products > Unified Communications > Unified Communications Applications > Presence Software > Unified Communications Manager IM & Presence Service.

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.

Source

• This vulnerability was found during the resolution of a support case.

URL

• http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160803-ucm

Revision History

• Version	Description	Section	Status	Date
  1.1	Added COP file for 11.5(1)	Fixed Software	Final	2016-August-05
  1.0	Initial public release.	-	Final	2016-August-03

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