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Security Intelligence Operations
Cisco IOS Software H.323 Remote Denial of Service Vulnerability |
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| Vulnerability Alert | Powered by  |
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| Threat Type: | Unintended Weakness: Denial of Service |
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| IntelliShield ID: | 18885 |
| Version: | 1 |
| First Published: | September 23, 2009 12:30 PM EDT |
| Last Published: | September 23, 2009 12:30 PM EDT |
| Vector: | Network |
| Authentication: | None |
| Exploit: | Functional |
| Port: | 1720 |
| CVE: | CVE-2009-2866 |
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| Urgency: |
Unlikely Use
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| Credibility: |
Confirmed
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| Severity: |
Mild Damage
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| CVSS Base: | 7.8 |
CVSS Calculator
CVSS Version 2
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| CVSS Temporal: | 6.4 |
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| Version Summary: | Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available. |
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| Description |
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Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
The vulnerability is in the affected device when it handles crafted H.323 packets. An unauthenticated, remote attacker could exploit this vulnerability by sending crafted H.323 packets to the affected system. When the device tries to process these packets, an unspecified error could occur that could cause the device to reload, resulting in a DoS condition.
Cisco has confirmed this vulnerability and released updated software. |
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| Warning Indicators |
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Cisco has published a list of affected Cisco IOS Software releases in the security advisory. The Vendor Announcements section of this alert contains a link to the advisory. |
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| IntelliShield Analysis |
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Only devices that are configured to process H.323 messages are vulnerable. H.323 message processing is disabled by default. Details on how to determine if this feature has been enabled are in the vendor advisory.
Exploitation requires the attacker to complete a three-way TCP handshake. For this reason the attacker will not be able to spoof the source address of the malicious H.323 packets.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available. |
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| Vendor Announcements |
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Cisco has released a security advisory to address Cisco bug ID CSCsz38104 at the following link: cisco-sa-20090923-h323 |
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| Impact |
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An unauthenticated, remote attacker could exploit this vulnerability to cause a DoS condition on the affected device. Repeated attacks could result in a persistent DoS condition. |
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| Technical Information |
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The vulnerability is in the H.323 processing component of the affected systems when it handles crafted H.323 packets. An unauthenticated, remote attacker could exploit this vulnerability by sending a series of crafted H.323 packets to the affected system on TCP port 1720. When the system tries to process these packets, it may reload, resulting in a DoS condition. |
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| Safeguards |
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Administrators are advised to apply the appropriate updates.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems on TCP port 1720.
The Cisco Applied Intelligence team has created the following companion document to guide administrators in identifying and mitigating attempts to exploit this vulnerability prior to applying updated software: cisco-amb-20090923-voice |
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| Patches/Software |
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Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via e-mail at tac@cisco.com. |
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| Signatures |
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| Alert History |
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Initial Release |
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Product Sets |
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The security vulnerability applies to the following combinations of products.
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LEGAL DISCLAIMER
The urgency and severity ratings of this alert are not tailored to individual users; users may value alerts differently based upon their network configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME. |
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