Summary

• Cisco IOS^® devices that are configured for Cisco Unified Communications Manager Express (CME) and the Extension Mobility feature are vulnerable to a buffer overflow vulnerability. Successful exploitation of this vulnerability may result in the execution of arbitrary code or a Denial of Service (DoS) condition on an affected device.

  Cisco has released software updates that address this vulnerability.

  This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090923-cme.

  Note: The September 23, 2009, Cisco IOS Security Advisory bundled publication includes eleven Security Advisories. Ten of the advisories address vulnerabilities in Cisco IOS Software, and one advisory addresses a vulnerability in Cisco Unified Communications Manager. Each advisory lists the releases that correct the vulnerability or vulnerabilities detailed in the advisory.

  Individual publication links are in "Cisco Event Response: Semiannual Cisco IOS Software Advisory Bundled Publication" at the following link:

  http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep09.html

Affected Products

• Cisco IOS devices, including Cisco Unified Communications 500 Series, that are configured for Cisco Unified CME and the Extension Mobility feature are affected.

  Vulnerable Products

  A Cisco IOS device that is configured for Cisco Unified CME and Extension Mobility contains the following output when the show running-config command is issued:

  ephone [Ethernet phone tag]
    ...
    logout-profile [logout-profile tag]

  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 is displayed 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 12.3(26) with an installed image name of C2500-IS-L:

      Router#show version
      Cisco Internetwork Operating System Software
      IOS (tm) 2500 Software (C2500-IS-L), Version 12.3(26), RELEASE SOFTWARE (fc2)
      Technical Support: http://www.cisco.com/techsupport
      Copyright (c) 1986-2008 by cisco Systems, Inc.
      Compiled Mon 17-Mar-08 14:39 by dchih
  
      
  

  The following example identifies a Cisco product that is running Cisco IOS Software Release 12.4(20)T with an installed image name of C1841-ADVENTERPRISEK9-M:

      Router#show version
      Cisco IOS Software, 1841 Software (C1841-ADVENTERPRISEK9-M), Version 12.4(20)T, RELEASE SOFTWARE (fc3)
      Technical Support: http://www.cisco.com/techsupport
      Copyright (c) 1986-2008 by Cisco Systems, Inc.
      Compiled Thu 10-Jul-08 20:25 by prod_rel_team
  
      
  

  Additional information about Cisco IOS Software release naming conventions is available in "White Paper: Cisco IOS Reference Guide" at the following link: http://www.cisco.com/warp/public/620/1.html .

  Products Confirmed Not Vulnerable

  Cisco IOS devices that are configured for Survivable Remote Site Telephony (SRST) Mode are not affected.

  Cisco IOS XR is not affected.

  Cisco IOS XE is not affected.

  Cisco Unified Communications Manager is not affected.

  Cisco Unified CME is not affected unless configured to use the Extension Mobility feature.

  No other Cisco products are currently known to be affected by these vulnerabilities.

Details

• Cisco Unified CME is the call processing component of an enhanced IP telephony solution that is integrated into Cisco IOS.

  The Extension Mobility feature in Cisco Unified CME provides the benefit of phone mobility for end users. A user login service allows phone users to temporarily access a physical phone other than their own phone and utilize their personal settings, such as directory number, speed-dial lists, and services, that is assigned to their own desk phone. The phone user can make and receive calls on that phone using the same personal directory number as is on their own desk phone. More information on Extension Mobility feature is available at the following URL:

  http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/admin/configuration/guide/cmemobl.html

  A vulnerability in the login section of the Extension Mobility feature may allow an unauthenticated attacker to execute arbitrary code or cause a Denial of Service (DoS) condition. Such packets can only come from registered phone IP addresses in the form of HTTP requests. If the auto-registration feature is enabled, an attacker can register its IP address and subsequently send a crafted payload to exploit this vulnerability. The auto-registration feature is enabled by default. More information on auto-registration can be found at the following link:

  http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/command/reference/cme_a1ht.html#wp1031242.

  This vulnerability is addressed by the Cisco Bug ID CSCsq58779 ( registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2009-2865.

Workarounds

• There are no workarounds to mitigate this vulnerability, other than disabling Extension Mobility. However, auto-registration can be disabled to make exploitation more difficult. Auto-registration can be disabled by the following command:

  telephony-service 
    no auto-reg-ephone 

  Before disabling auto-registration, all phone MAC addresses need to be explicitly defined on the Cisco Unified CME. Otherwise phones will not be able to register. More information on auto-registration can be found at the following link:

  http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/command/reference/cme_a1ht.html#wp1031242

  Additional mitigations that can be deployed on Cisco devices in the network are available in the Cisco Applied Mitigation Bulletin companion document for this advisory, which is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20090923-cme

Fixed Software

• When considering software upgrades, also consult http://www.cisco.com/go/psirt and any subsequent advisories to determine exposure and a complete upgrade solution.

  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.

  Each row of the Cisco IOS software table (below) names a Cisco IOS release train. If a given release train is vulnerable, then the earliest possible releases that contain the fix (along with the anticipated date of availability for each, if applicable) are listed in the "First Fixed Release" column of the table. The "Recommended Release" column indicates the releases which have fixes for all the published vulnerabilities at the time of this Advisory. A device running a release in the given train that is earlier than the release in a specific column (less than the First Fixed Release) is known to be vulnerable. Cisco recommends upgrading to a release equal to or later than the release in the "Recommended Releases" column of the table.

  Major Release	Availability of Repaired Releases
  Affected 12.0-Based Releases	First Fixed Release	Recommended Release
  There are no affected 12.0 based releases.
  Affected 12.1-Based Releases	First Fixed Release	Recommended Release
  There are no affected 12.1 based releases.
  Affected 12.2-Based Releases	First Fixed Release	Recommended Release
  There are no affected 12.2 based releases.
  Affected 12.3-Based Releases	First Fixed Release	Recommended Release
  There are no affected 12.3 based releases.
  Affected 12.4-Based Releases	First Fixed Release	Recommended Release
  12.4	Not Vulnerable
  12.4GC	Not Vulnerable
  12.4JA	Not Vulnerable
  12.4JDA	Not Vulnerable
  12.4JDC	Not Vulnerable
  12.4JDD	Not Vulnerable
  12.4JK	Not Vulnerable
  12.4JL	Not Vulnerable
  12.4JMA	Not Vulnerable
  12.4JMB	Not Vulnerable
  12.4JX	Not Vulnerable
  12.4MD	Not Vulnerable
  12.4MDA	Not Vulnerable
  12.4MR	Not Vulnerable
  12.4SW	Not Vulnerable
  12.4T	Not Vulnerable
  12.4XA	Not Vulnerable
  12.4XB	Not Vulnerable
  12.4XC	Not Vulnerable
  12.4XD	Not Vulnerable
  12.4XE	Not Vulnerable
  12.4XF	Not Vulnerable
  12.4XG	Not Vulnerable
  12.4XJ	Not Vulnerable
  12.4XK	Not Vulnerable
  12.4XL	Not Vulnerable
  12.4XM	Not Vulnerable
  12.4XN	Not Vulnerable
  12.4XP	Not Vulnerable
  12.4XQ	Not Vulnerable
  12.4XR	Not Vulnerable
  12.4XT	Not Vulnerable
  12.4XV	Not Vulnerable
  12.4XW	12.4(11)XW8	12.4(20)T4 12.4(22)T3 12.4(24)T2; Available on 23-OCT-2009
  12.4XY	12.4(15)XY4	12.4(20)T4 12.4(22)T3 12.4(24)T2; Available on 23-OCT-2009
  12.4XZ	12.4(15)XZ1	12.4(20)T4 12.4(22)T3 12.4(24)T2; Available on 23-OCT-2009
  12.4YA	12.4(20)YA1	12.4(20)T4 12.4(22)T3 12.4(24)T2; Available on 23-OCT-2009
  12.4YB	Not Vulnerable
  12.4YD	Not Vulnerable
  12.4YE	Not Vulnerable

Exploitation and Public Announcements

• The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.

  This vulnerability was found internally.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090923-cme

Revision History

• Revision 1.0

  2009-September-23

  Initial public release

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