Cisco Security Advisory
Click Icon to Copy Verbose Score
AV:N/AC:H/Au:N/C:N/I:N/A:C/E:F/RL:OF/RC:C
-
A vulnerability in the VPN authentication code that handles parsing of the username from the certificate on the Cisco ASA firewall could allow an unauthenticated, remote attacker to cause a reload of the affected device.
The vulnerability is due to parallel processing of a large number of Internet Key Exchange (IKE) requests for which username-from-cert is configured. An attacker could exploit this vulnerability by sending a large number of IKE requests when the affected device is configured with the username-from-cert command. An exploit could allow the attacker to cause a reload of the affected device, leading to a denial of service (DoS) condition.
Cisco has confirmed the vulnerability in a security notice and released software updates.
To exploit this vulnerability, an attacker must send a large number of IKE requests to a targeted device, which may reside on trusted, internal networks that the attacker would likely need to access. This access requirement decreases the likelihood of a successful exploit. In addition, the targeted device must be configured with the username-from-cert command.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
-
Customers are advised to consult Cisco bug ID CSCua91108 for a complete list of affected product versions.
-
Administrators are advised to apply the appropriate updates.
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.
-
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.
-
The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
-
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
-
Show LessVersion Description Section Status Date 1.0 Initial Release NA Final 2013-Oct-22
-
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A stand-alone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy, and may lack important information or contain factual errors. The information in this document is intended for end-users of Cisco products.