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Security Intelligence Operations
Cisco IOS Software Session Initiation Protocol Message Memory Leak 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: | 16651 |
| Version: | 1 |
| First Published: | September 24, 2008 01:26 PM EDT |
| Last Published: | September 24, 2008 01:26 PM EDT |
| Vector: | Network |
| Authentication: | None |
| Exploit: | Functional |
| Port: | 5060 |
| CVE: | CVE-2008-3799 |
| BugTraq ID: | 31361 |
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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 when processing SIP messages as a part of VoIP services 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 products contain a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
The vulnerability exists due to an error when these products process Session Initiation Protocol (SIP) messages when providing Voice over IP (VoIP) services. A memory leak can occur during the processing of valid SIP messages. After repeated exploitation, the VoIP services on the affected device may stop processing requests. This could result in a DoS condition on any telephony services that were being provided. In addition, the excessive consumption of system memory by the VoIP handling services may cause the affected device to process traffic more slowly than usual. If the exploitation continues, it may result in a reload or prevent the device from processing requests altogether.
Functional exploit code exists.
Cisco has confirmed this vulnerability in a security advisory and released updated software. |
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| Warning Indicators |
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A complete list of affected Cisco IOS devices is available at the following link: cisco-sa-20080924-sip
Systems running an affected Cisco IOS version are vulnerable only if they have been configured to process SIP messages as a part of VoIP services. Systems that allow SIP messages to pass through or that only perform network address translation (NAT) on transiting SIP messages are not affected. |
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| IntelliShield Analysis |
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Although in most cases it would be necessary for VoIP services to be explicitly enabled on a device, such as by using a dial-peer command, many older versions of Cisco IOS Software enabled SIP processing by default. This was documented in bug ID CSCsb25337, as described in IntelliShield Alert 12580. A fix was made available as well. Systems that were affected by the vulnerability associated with this bug ID and not yet patched would also be susceptible to exploitation of the vulnerability described in this alert.
Cisco indicated through CVSS scoring the existence of functional exploit code; however, this exploit code is not known to be publicly available. |
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| Vendor Announcements |
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Cisco has released a security advisory for Cisco Bug ID CSCse56800 at the following link: cisco-sa-20080924-sip |
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| Impact |
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An unauthenticated, remote attacker could exploit this vulnerability to cause the affected system to needlessly allocate large amounts of system memory. This memory allocation may result in traffic processing that is slower than normal or possibly cause a reload of the affected device. In any event, exploitation may result in a DoS condition on telephony services, which would prevent the handling of SIP messages as a part of VoIP processing. |
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| Technical Information |
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This vulnerability can occur on an affected device during the processing of valid SIP messages. If the device has a listener for SIP traffic, which is likely to be on UDP or TCP port 5060, an unauthenticated, remote attacker could exploit this vulnerability by sending valid SIP messages to the affected system. SIP messages that meet certain undisclosed criteria can cause the services that handle SIP traffic as a part of VoIP processing to consume system memory unnecessarily. Repeatedly sending malicious SIP messages to an affected system can cause the VoIP processing service to stop handling requests, resulting in a DoS condition.
Excessive use of system memory on the device by the affected service may also slow the response time of the device, potentially leading to a reload or a device state in which requests are no longer processed. In either case, the result would be a complete DoS condition on the affected device. |
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| Safeguards |
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Administrators are advised to apply the appropriate patches.
Administrators are advised to disable the processing of SIP messages by any VoIP services if they are not needed for business purposes.
Administrators are advised to monitor critical systems for signs of exploitation.
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-20080924-sip |
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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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| 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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