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Vulnerability Alert

Cisco IOS Software ICMP Processing Denial of Service Vulnerability

 
Threat Type:CWE-20: Input Validation
IntelliShield ID:31874
Version:1
First Published:2013 November 22 17:52 GMT
Last Published:2013 November 22 17:52 GMT
Port: Not available
CVE:CVE-2013-6694
BugTraq ID:63874
Urgency:Unlikely Use
Credibility:Confirmed
Severity:Mild Damage
CVSS Base:4.3 CVSS Calculator
CVSS Version 2.0
CVSS Temporal:4.1
 
Version Summary:Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are not available.
 
 
Description
A vulnerability in IPSec tunnel implementation of Cisco IOS Software could allow an unauthenticated, remote attacker to change the tunnel MTU or path MTU and potentially cause IPSec tunnels to drop.

The vulnerability is due to incorrect processing of certain ICMP packets. An attacker could exploit this vulnerability by sending specific ICMP packets to an affected device in order to change the configured MTU value of the tunnel interface. An exploit could allow the attacker to change the tunnel MTU or path MTU and potentially cause IPSec tunnels to drop.

Cisco has confirmed the vulnerability in a security notice; however, software updates are not available.
 
Warning Indicators
At the time this alert was first published, Cisco IOS Software Releases 15.2(4)M and prior were vulnerable. Later releases of Cisco IOS Software may also be vulnerable.
 
IntelliShield Analysis
To exploit this vulnerability, the attacker may need access to trusted, internal networks, in which the targeted device may reside, to send specific ICMP packets to be processed by the device. This access requirement could limit the possibility of a successful exploit.

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 notice at the following link: CVE-2013-6694

Customers are advised to consult Cisco bug ID CSCul29918 for the most complete list of affected product versions.
 
Impact
An unauthenticated, remote attacker could exploit this vulnerability to cause IPSec tunnels to drop, which could lead to a DoS condition.
 
Technical Information
The vulnerability is due to incorrect processing of certain ICMP packets by the affected software.

An unauthenticated, remote attacker could exploit this vulnerability by sending specific ICMP packets to an affected device designed to change the configured MTU value of the tunnel interface. An exploit could allow the attacker to change the tunnel MTU or path MTU and potentially cause IPSec tunnels to drop, resulting in DoS condition.
 
Safeguards
Administrators are advised to contact the vendor regarding future updates and releases.

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

Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.

Administrators are advised to monitor affected systems.
 
Patches/Software
Software updates are not available.
 
Alert History
 
Initial Release


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

Primary Products:
CiscoIOS 15.2M 15.2(4)M

Associated Products:
N/A




Alerts and bulletins on the Cisco Security Intelligence Operations Portal are highlighted by analysts in the Cisco Threat Operations Center and represent a subset of the comprehensive content that is available through Cisco Security IntelliShield Alert Manager Service. This customizable threat and vulnerability alert service provides security staff with access to timely, accurate, and credible information about threats and vulnerabilities that may affect their environment.


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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