Vulnerability Alert

Cisco IOS Software RSVP Denial of Service Vulnerability

 
Threat Type:CWE-399: Resource Management Errors
IntelliShield ID:25369
Version:1
First Published:2012 March 28 16:19 GMT
Last Published:2012 March 28 16:19 GMT
Port: Not available
CVE:CVE-2012-1311
Urgency:Unlikely Use
Credibility:Confirmed
Severity:Mild Damage
CVSS Base:7.8 CVSS Calculator
CVSS Version 2.0
CVSS Temporal:6.4
 
Version Summary:

Cisco IOS Software and Cisco IOS XE Software contain a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.

 
 
Description

Cisco IOS Software and Cisco IOS XE Software contain a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.

The vulnerability is due to errors in the RSVP feature. An unauthenticated, remote attacker could exploit this vulnerability to cause the targeted device to stop responding, resulting in a DoS condition.

Cisco confirmed the vulnerability in a security advisory and released updated software.

 
Warning Indicators

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.

Only specific configurations on affected devices are vulnerable. A device is vulnerable if both the following conditions are met:

  • A VPN routing and forwarding (VRF) instance is configured without RSVP
  • At least one other interface (physical or virtual), not in the same VRF, is configured with RSVP
 
IntelliShield Analysis

To exploit this vulnerability, the attacker would need knowledge of the affected infrastructure and the ability to submit RSVP packets to the targeted system. To achieve this objective, the attacker may need access to trusted, internal network resources.  This access requirement reduces the exposure of this vulnerability.

Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.

 
Vendor Announcements

Cisco has released a security advisory for Cisco bug ID CSCts80643 at the following link: cisco-sa-20120328-rsvp

 
Impact

An unauthenticated, remote attacker could exploit this vulnerability to cause a targeted device to stop responding.  Sustained attacks could result in a DoS condition.

 
Technical Information

The vulnerability is due to errors in the RSVP feature when used on a device configured with VRF instances.

An unauthenticated, remote attacker with limited knowledge of the targeted infrastructure could exploit this vulnerability by submitting valid, crafted RSVP packets with set conditions to an affected device, resulting in a wedge of the receive queue of any RSVP ingress interface. The resulting interface wedge could lead to loss of connectivity, loss of routing protocol adjacency, or other DoS conditions.

 
Safeguards

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 devices.

Administrators are advised to allow only trusted users to have network access.

Administrators are advised to monitor affected systems.

 
Patches/Software

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.

 
Alert History
 

Initial Release



Product Sets
 
The security vulnerability applies to the following combinations of products.

Primary Products:
CiscoIOS 15.0M Base, 15.0(1)M, 15.0(1)M1, 15.0(1)M2, 15.0(1)M3, 15.0(1)M4, 15.0(1)M5, 15.0(1)M6, 15.0(1)M6a, 15.0(1)M7 | 15.0SY 15.0(1)SY | 15.0XA Base, 15.0(1)XA, 15.0(1)XA1, 15.0(1)XA2, 15.0(1)XA3, 15.0(1)XA4, 15.0(1)XA5 | 15.1EY 15.1(2)EY, 15.1(2)EY1, 15.1(2)EY1a | 15.1GC Base, 15.1(2)GC, 15.1(2)GC1 | 15.1M 15.1(4)M, 15.1(4)M0a, 15.1(4)M0b, 15.1(4)M1, 15.1(4)M2 | 15.1MR 15.1(1)MR, 15.1(1)MR1, 15.1(1)MR2, 15.1(1)MR3 | 15.1S Base, 15.1(1)S, 15.1(1)S1, 15.1(1)S2, 15.1(2)S, 15.1(2)S1, 15.1(2)S2, 15.1(3)S, 15.1(3)S0a, 15.1(3)S1 | 15.1SNG 15.1(2)SNG | 15.1T Base, 15.1(1)T, 15.1(1)T1, 15.1(1)T2, 15.1(1)T3, 15.1(1)T4, 15.1(1)T5, 15.1(2)T, 15.1(2)T0a, 15.1(2)T1, 15.1(2)T2, 15.1(2)T2a, 15.1(2)T3, 15.1(2)T4, 15.1(3)T, 15.1(3)T1, 15.1(3)T2 | 15.1XB Base, 15.1(1)XB, 15.1(1)XB1, 15.1(1)XB2, 15.1(1)XB3, 15.1(4)XB4, 15.1(4)XB5, 15.1(4)XB5a, 15.1(4)XB6
CiscoCisco IOS XE Software 3.2S .0, .1, .2 | 3.3S .0, .1, .2 | 3.4S .0, .1 | 3.5S Base

Associated Products:
CiscoIOS 15.0M | 15.0SY | 15.0XA | 15.1EY | 15.1GC | 15.1M | 15.1MR | 15.1S | 15.1SA 15.1(1)SA, 15.1(1)SA1, 15.1(1)SA2 | 15.1SNG | 15.1T | 15.1XB
CiscoCisco IOS XE Software 3.2S | 3.3S | 3.4S




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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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