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.
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.
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.
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.
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.
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.
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.
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.
Administrators are advised to monitor affected systems.
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 firstname.lastname@example.org for assistance.
The security vulnerability applies to the following combinations of products.
Cisco Adaptive Security Appliance (ASA) Software
8.4 .5, .5.6, .6 | 9.1 .1, .2
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.