Cisco CallManager Memory Handling Vulnerabilities

Summary

• Cisco CallManager (CCM) is the software-based call-processing component of the Cisco IP telephony solution which extends enterprise telephony features and functions to packet telephony network devices such as IP phones, media processing devices, voice-over-IP (VoIP) gateways, and multimedia applications. Cisco CallManager 3.3 and earlier, 4.0, and 4.1 are vulnerable to Denial of Service (DoS) attacks, memory leaks, and memory corruption which may result in services being interrupted, servers rebooting, or arbitrary code being executed.

  Cisco has made free software available to address these vulnerabilities.

  This advisory will be posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20050712-ccm.

Affected Products

• This section provides details on affected products.

  Vulnerable Products

  These products are vulnerable:

  • Cisco CallManager 3.2 and earlier
    
  • Cisco CallManager 3.3, versions earlier than 3.3(5)
    
  • Cisco CallManager 4.0, versions earlier than 4.0(2a)SR2b
    
  • Cisco CallManager 4.1, versions earlier than 4.1(3)SR1
    

  Products Confirmed Not Vulnerable

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

Details

• This section provides detailed information about these vulnerabilities.

  • CSCed37403 ( registered customers only) -- Resource leak with RISDC -- CallManager does not time out RISDC (Realtime Information Server Data Collection) sockets aggressively enough, leading to a scenario where TaskManager indicates that RisDC.exe is using large amounts of non-paged pool memory and ports remain in the Close_Wait state. Non-paged pool memory allocation can be checked by opening Microsoft Windows Task Manager, going to the View menu, choosing Select Columns and selecting Non-paged Pool. Open ports are listed in the output of the netstat -an command.
    
  • CSCee00116 ( registered customers only) -- Cisco CallManager CTI Manager may restart with greater than 1GB memory used -- Repeated attacks with crafted packets can cause the CTI Manager to allocate greater than 1 gigabyte of virtual memory. Memory allocation of the ctimgr.exe process can be checked by viewing the Microsoft Windows Task Manager.
    
  • CSCee00118 ( registered customers only) -- CallManager may restart with repeated attacks -- Crafted packets can cause the CallManager to inappropriately allocate 500MB to the ccm.exe process, which will return to the memory pool under normal conditions. Repeated attacks may cause a CallManager under load to exhaust memory resources and restart. Memory allocation of the ccm.exe process can be checked by viewing the Microsoft Windows Task Manager. Under attack, ccm.exe memory will jump repeatedly by 500MB.
    
  • CSCef47060 ( registered customers only) -- Failed logins create memory leak when MLA enabled -- When MLA (Multi Level Admin) is enabled and there are repeated, failed logons for the AST (Admin Service Tool) a memory leak may occur. While under normal operations inetinfo.exe will use between 20Mb and 30Mb of memory, systems facing this issue showed up to 750Mb of memory used. Memory allocation of the inetinfo.exe process can be checked by viewing the Microsoft Windows Task Manager. MLA is not on by default and the enable status can be checked under CCM/User/Access Rights/MLA Parameters/Enable Multi Level Admin.
    
  • CSCsa75554 ( registered customers only) -- Vulnerability to DoS and remote execution in aupair service -- Crafted packets directed at Cisco CallManager may cause a memory allocation failure and buffer overflow resulting in potential execution of arbitrary code, abnormal termination of the aupair process, or corruption of memory. The aupair.exe process is a database layer between ccm.exe and SQL which cannot be disabled for normal Cisco CallManager operation. When viewing Microsoft Windows Task Manager, the process is aupair.exe, but under the Service Control Manager it is called Cisco Database Layer Monitor. If the aupair.exe process terminates, a message will be logged to the events monitor and a drwatson report will be generated.
    

Workarounds

• The effectiveness of any workaround is dependent on specific customer situations such as product mix, network topology, traffic behavior, and organizational mission. Due to the variety of affected products and releases, customers should consult with their service provider or support organization to ensure any applied workaround is the most appropriate for use in the intended network before it is deployed.

  While there are no workarounds available on the Cisco CallManager to eliminate attacks, securing the voice network with Cisco CallManager security best practices may lessen the risk or mitigate the effects of these vulnerabilities. By using access lists to restrict access to the Cisco CallManager, the risk of successful attack is greatly reduced. Please refer to the SAFE: IP Telephony Security in Depth white paper located off the SAFE Blueprint http://www.cisco.com/go/safe introduction page. Also, Cisco provides Solution Reference Network Design (SRND) guides to help design and deploy networking solutions. http://www.cisco.com/warp/public/779/largeent/it/ese/srnd.html

  The specific access list examples given below need to be tailored for each network's needs and added to the other access list entries in place. If you have gateways or other devices outside of the CallManager VLAN, you can configure specific ACL entries permitting access from those device IP addresses. See the list of CallManager ports used http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a00801a62b9.shtml

  • CSCed37403 -- To secure the Cisco CallManager cluster the following ports should be blocked between the CCM cluster and the rest of the network:
    Access-list 100 deny tcp any eq 2555
    Access-list 100 deny tcp any eq 2556
    
  • CSCee00116, CSCee00118 -- To secure the Cisco CallManager cluster the following ports should be blocked between the CCM cluster and the rest of the network:
    UDP 1719 - H.323 RAS
    TCP 1720 - H.323 H.225
    TCP 2001 - SCCP
    TCP 2002 - SCCP
    TCP 2428 - MGCP
    TCP 2748 - TAPI/JTAPI Applications
    Access-list 100 deny tcp any eq 1719
    Access-list 100 deny tcp any eq 1720
    Access-list 100 deny tcp any eq 2001
    Access-list 100 deny tcp any eq 2002
    Access-list 100 deny tcp any eq 2428
    Access-list 100 deny tcp any eq 2748
    If there are devices that need to have access to any of these ports from outside the secured CallManager VLAN(s), permit those device IP's explicitly. Example devices include Voice Gateways, TAPI/JTAPI Softphones, as well as other Voice Application Servers such as IPCC Express, etc.
    Port 2000 is the last port that needs to be secured. Port 2000 is used by Skinny/SCCP IP Phones to communicate with the CallManager. Permit only traffic coming from the Voice VLAN’s to access port 2000.
    Access-list 100 permit tcp eq 2000
    Note: If IP Communicator is used on the data VLAN, specific ACL entries can be added to allow IP Communicator operation.
    
  • CSCef47060 -- This vulnerability is only applicable if you have enabled MLA (Multi Level Administration) and you are running Cisco CallManager 4.0(2) without SR1 (Service Release) or later. All other releases are not vulnerable. MLA is not on by default and the enable status can be checked under CCM/User/Access Rights/MLA Parameters/Enable Multi Level Admin. Disabling and re-enabling will release excess memory used, mitigating the effects of an attack. For a vulnerable server, TCP port 80 needs to be secured in order to limit access to the web pages. This can be done in two ways:
    1) Permit only trusted IP addresses access to this port until a patch can be applied. Users will not be able to access Phone Services, Directory & CCMUser pages. The following ACL will turn off web access completely.
    Access-list 100 deny tcp any eq 80
    2) Configure Windows IIS so that MLA related virtual directories permit access only to specific IP’s, while other directories are left open for user access.
    How to enable Internet Information Services (IIS) IP Address Access Restrictions:
    1. Click Start > Programs > Administrative Tools > Internet Services Manager to open the IIS management console.
    2. Select Internet Information Services > [Computer Name] > Default Web Site.
    3. Right click the CCMAdmin virtual directory and select Properties.
    4. Click the Directory Security tab.
    5. Click Edit for IP address and domain name restrictions.
    6. Select Denied Access.
    7. Click Add.
    8. Select Single Computer or Group of Computers.
    9. Type the IP Address or Network ID and Subnet Mask to be granted access.
    10. Click OK.
    11. Repeat Steps 7 - 10 until all desired IP Addresses or Networks have been granted access.
    12. Click OK.
    13. Return to Step 3 and repeat the steps for the following virtual directories: CCMService, CCMTraceAnalysis, AST, RTMTReports, SOAP.
    14. Click OK out of all the open windows.
    15. Test connectivity from an allowed and denied IP address to confirm the filter is in place.
    
  • CSCsa75554 -- To secure the Cisco CallManager cluster block port 8001 between the CCM cluster and the rest of the network:
    Access-list 100 deny tcp any eq 8001
    If there are Cisco CallManagers that need access to this service from outside the secured CallManager VLAN, permit those device IP addresses explicitly.
    

Fixed Software

• When considering software upgrades, please also consult http://www.cisco.com/en/US/products/products_security_advisories_listing.html 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") for assistance.

  Each row of the Cisco CallManager software table (below) describes a release train which will address all of the vulnerabilities mentioned in this advisory. If a given release train is vulnerable, then the earliest possible releases that contain the fixes (the "First Fixed Release") and the anticipated date of availability for each are listed in the "Engineering Special," "Service Release," and "Maintenance Release" columns. A device running a Cisco CallManager release in the given train that is earlier than the release in a specific column (less than the First Fixed Release listed in the Engineering Special or Special Release columns) is known to be vulnerable to one or more issues. The Cisco CallManager should be upgraded at least to the indicated release or a later version (greater than or equal to the First Fixed Release label).

  Train	Engineering Special	Service Release	Maintenance Release
  3.2 and earlier			migrate to 3.3 or later
  3.3	3.3(3)ES61 3.3 (4)ES25		3.3(5)
  4.0	4.0(2a)ES40	4.0(2a)SR2b	no release planned
  4.1	4.1(2)ES33 4.1 (3)ES07	4.1(3)SR1	no release planned

Exploitation and Public Announcements

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

  The aupair service vulnerability (CSCsa75554) was reported to Cisco by Internet Security Systems who will also be making public announcements regarding this issue.

  Jeff Fay from PatchAdvisor will issue a report on his findings of CSCee00116 on their vulnerability alert service.

URL

• http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20050712-ccm

Revision History

• Revision 1.1	2005-July-18	Workaround section added example of restricting access to the Cisco Call Manager.
  Revision 1.0	2005-July-12	Initial public release.

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