Vulnerability Alert

Cisco ASA Protocol Inspection Connection Table Denial of Service Vulnerability

 
Threat Type:CWE-399: Resource Management Errors
IntelliShield ID:30607
Version:1
First Published:2013 August 30 14:22 GMT
Last Published:2013 August 30 14:22 GMT
Port: Not available
CVE:CVE-2013-3463
BugTraq ID:62068
Urgency:Unlikely Use
Credibility:Confirmed
Severity:Mild Damage
CVSS Base:4.3 CVSS Calculator
CVSS Version 2.0
CVSS Temporal:3.6
 
Version Summary:Cisco Adaptive Security Appliance Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
 
 
Description
Cisco Adaptive Security Appliance (ASA) Software contains a vulnerability that could allow an unauthenticated, remote attacker to fill the connection table in the ASA preventing new connections to be established through the device.

The vulnerability is due to the ASA not honoring the idle timeout for some protocol inspected connections. An attacker could exploit this vulnerability by sending several crafted requests for one or more protocols configured for inspection on the ASA. A successful exploit could allow the attacker to force the ASA to stop accepting new connections, resulting in a denial of service (DoS) condition.

Cisco has confirmed the vulnerability in a security notice and released software updates.
 
Warning Indicators
At the time this alert was first published, Cisco ASA Software versions 9.1.2 and prior were vulnerable. Later releases of Cisco ASA Software may also be vulnerable.
 
IntelliShield Analysis
To exploit this vulnerability, an attacker may require access to trusted, internal networks to send crafted requests to an affected device. This access requirement could limit the likelihood of a successful exploit.
 
Vendor Announcements
Cisco has released a security notice at the following link: CVE-2013-3463

Customers are advised to consult Cisco bug IDs CSCuh13899 for the most complete list of affected product versions.
 
Impact
An unauthenticated, remote attacker could exploit this vulnerability to fill the connection table in an affected device. Successful exploitation could prevent new connections from being established, resulting in a DoS condition.
 
Technical Information
The vulnerability is due to improper handling of the idle timeout feature imposed by the affected software for some protocol inspected connections.

An unauthenticated, remote attacker could exploit this vulnerability by sending crafted requested for one or more protocols configured to be inspected by an affected device. Processing the requests could force the device to stop accepting new connections, resulting in a DoS condition.
 
Safeguards
Administrators are advised to apply the appropriate updates.

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

Understanding activity on the network provides information and visibility that can be used to identify potential security incidents. Organizations should log events from devices and review the logged data to provide insight into anomalies or malicious activity. For logging best practices, see Cisco Guide to Harden Cisco IOS Devices.

It is critical to prevent unauthorized direct communication to network devices. Restrict network traffic destined for the network infrastructure to protect against reconnaissance and DoS attacks. For configuration details, see Protecting Your Core: Infrastructure Protection Access Control Lists.

Administrators are advised to monitor affected systems.
 
Patches/Software
Cisco customers with active contracts should contact their Cisco support team for assistance in upgrading to a software version that includes fixes for this vulnerability. Cisco customers without contracts may contact the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at tac@cisco.com for assistance.
 
Alert History
 
Initial Release


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

Primary Products:
CiscoCisco Adaptive Security Appliance (ASA) Software 8.4 .5, .5.6, .6 | 9.1 .1, .2

Associated Products:
N/A




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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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