AV:N/AC:L/Au:N/C:N/I:N/A:C/E:F/RL:OF/RC:C
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The H.323 implementation in Cisco IOS® Software contains a vulnerability that can be exploited remotely to cause a device that is running Cisco IOS Software to reload.
Cisco has released software updates that address this vulnerability. There are no workarounds to mitigate the vulnerability apart from disabling H.323 if the device that is running Cisco IOS Software does not need to run H.323 for VoIP services.
This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090923-h323.
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
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Vulnerable Products
Cisco devices that are running affected Cisco IOS Software versions that are configured to process H.323 messages are affected by this vulnerability. H.323 is not enabled by default.
To determine the Cisco IOS Software device is running H.323 services use the show process cpu | include 323 command, as shown in the following example:
Router#show process cpu | include 323 249 16000 3 5333 0.00% 0.00% 0.00% 0 CCH323_CT 250 0 1 0 0.00% 0.00% 0.00% 0 CCH323_DNS Router#
Note: Only H.323 listening port TCP 1720 is affected.
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 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 !--- output truncated
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 !--- output truncated
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 XE and Cisco IOS XR Software are not affected by this vulnerability. No other Cisco products are currently known to be affected by this vulnerability.
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H.323 is the ITU standard for real-time multimedia communications and conferencing over packet-based (IP) networks. A subset of the H.323 standard is H.225.0, a standard used for call signalling protocols and media stream packetization over IP networks.
The H.323 implementation in Cisco IOS Software contains a vulnerability. An attacker can exploit this vulnerability remotely by sending an H.323 crafted packet to the affected device that is running Cisco IOS Software. A TCP three-way handshake is needed to exploit this vulnerability.
This vulnerability is documented in Cisco bug ID CSCsz38104 ( registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2009-2866.
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There are no workarounds to mitigate the vulnerability apart from disabling H.323 if the Cisco IOS device does not need to run H.323 for VoIP services. Affected devices that must run H.323 are vulnerable, and there are not any specific configurations that can be used to protect them. Applying access lists on interfaces that should not accept H.323 traffic and putting firewalls in strategic locations may greatly reduce exposure until an upgrade can be performed.
Cisco provides Solution Reference Network Design (SRND) guides to help design and deploy networking solutions, which can be found at http://www.cisco.com/go/srnd Voice Security best practices are covered in the Cisco Unified Communications SRND Based on Cisco Unified Communications Manager 6.x at http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/6x/security.html.
Below is an example of an access list to block H.323 management traffic from anywhere but a permitted network. In this example, the permitted network is 172.16.0.0/16.
!--- Permit access from any IP address in the 172.16.0.0/16 !--- network to anywhere on port 1720. access-list 101 permit tcp 172.16.0.0 0.0.255.255 any eq 1720 !--- Permit access from anywhere to a host in the !--- 172.16.0.0/26 network on port 1720. access-list 101 permit tcp any 172.16.0.0 0.0.255.255 eq 1720 !--- Deny all traffic from port 1720. access-list 101 deny tcp any eq 1720 any !--- Deny all traffic to port 1720. access-list 101 deny tcp any any eq 1720 !--- Permit all other traffic. access-list 101 permit ip any any
Alternatively, you can use the call service stop forced command under the voice service voip mode, as shown in the following example:
voice service voip h323 call service stop forced
Additional mitigations that can be deployed on Cisco devices within the network are available in the companion document "Cisco Applied Mitigation Bulletin: Identifying and Mitigating Exploitation of the Denial of Service Vulnerabilities in Cisco Unified Communications Manager and Cisco IOS Software", which is available at the following location: https://sec.cloudapps.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20090923-voice.
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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 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
Not Vulnerable
Vulnerable; first fixed in 12.4
Releases up to and including 12.2(4)B8 are not vulnerable.
12.4(25b)
12.4(23b)
Not Vulnerable
Not Vulnerable
Vulnerable; first fixed in 12.4
Releases up to and including 12.2(15)BX are not vulnerable.
12.4(25b)
12.4(23b)
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Vulnerable; migrate to 12.2SB
12.2(33)SB7
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Releases up to and including 12.2(15)MC1 are not vulnerable.
Releases 12.2(15)MC2b and later are not vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Vulnerable; first fixed in 12.4
Releases up to and including 12.2(8)T10 are not vulnerable.
12.4(25b)
12.4(23b)
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
12.2XND
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Not Vulnerable
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Releases prior to 12.2(11)YV1 are vulnerable, release 12.2(11)YV1 and later are not vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Not Vulnerable
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Affected 12.3-Based Releases
First Fixed Release
Recommended Release
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Releases up to and including 12.3(2)JK3 are not vulnerable.
Releases 12.3(8)JK1 and later are not vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Not Vulnerable
Not Vulnerable
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Releases up to and including 12.3(4)TPC11a are not vulnerable.
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Releases prior to 12.3(2)XA7 are vulnerable, release 12.3(2)XA7 and later are not vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Note: Releases prior to 12.3(7)XI11 are vulnerable, release 12.3(7)XI11 and later are not vulnerable;
12.2(33)SB7
12.2(31)SB16
Vulnerable; migrate to any release in 12.4XN
12.4(15)T10
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Not Vulnerable
Vulnerable; first fixed in 12.4T
Releases up to and including 12.3(8)XU1 are not vulnerable.
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; migrate to any release in 12.4XR
12.4(15)XR7
12.4(22)XR
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Vulnerable; first fixed in 12.4
12.4(25b)
12.4(23b)
Not Vulnerable
Not Vulnerable
Vulnerable; migrate to any release in 12.4XR
12.4(15)XR7
12.4(22)XR
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Not Vulnerable
Not Vulnerable
Not Vulnerable
Releases prior to 12.3(11)YK3 are vulnerable, release 12.3(11)YK3 and later are not vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
Releases up to and including 12.3(11)YS1 are not vulnerable.
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; migrate to 12.4XR
12.4(15)XR7
12.4(22)XR
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Affected 12.4-Based Releases
First Fixed Release
Recommended Release
12.4(25b)
12.4(23b)
12.4(25b)
12.4(23b)
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Releases prior to 12.4(19)MR3 are vulnerable, release 12.4(19)MR3 and later are not vulnerable
Not Vulnerable
12.4(15)T10
12.4(20)T4
12.4(22)T2
12.4(24)T1
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Not Vulnerable
Not Vulnerable
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Not Vulnerable
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; first fixed in 12.4T
Releases up to and including 12.4(15)XM are not vulnerable.
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Not Vulnerable
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Not Vulnerable
Not Vulnerable
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; Contact your support organization per the instructions in Obtaining Fixed Software section of this advisory
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
Vulnerable; first fixed in 12.4T
12.4(15)T10
12.4(20)T4
12.4(22)T3
12.4(24)T2; Available on 23-OCT-2009
12.4(22)YB4
12.4(22)YB4
Not Vulnerable
Not Vulnerable
Note: No Cisco IOS-XE Software or Cisco IOS Software Modularity releases are affected by this vulnerability.
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The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.
This vulnerability was found during internal testing.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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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 is an uncontrolled copy, and may lack important information or contain factual errors. The information in this document is intended for end-users of Cisco products.