A vulnerability in the WebVPN feature of Cisco Adaptive Security Appliance (ASA) could allow an unauthenticated, remote attacker to force the ASA to stop accepting new SSL connections.
The vulnerability is due to a memory leak in the WebVPN embedded web server. An attacker could exploit this vulnerability by sending a large number of crafted HTTP requests to the ASA.
Cisco has confirmed the vulnerability in a security notice and released software updates.
To exploit this vulnerability, an attacker may need access to trusted, internal networks to send large amounts of crafted HTTP requests to a targeted device. This access requirement may reduce the likelihood of a successful exploit.
Customers are advised to consult Cisco bug ID CSCue05458 for a complete list of affected product versions.
Vulnerable ProductsAt the time this alert was first published, Cisco ASA Software Releases 9.1(.1.4) and prior were vulnerable. Later releases of Cisco ASA Software may also be vulnerable.
Products Confirmed Not VulnerableNo other Cisco products are currently known to be affected by these vulnerabilities.
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 can help protect affected systems from external attacks by using a solid firewall strategy.
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 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.
Version Description Section Status Date 1.0 Initial Release NA Final 2015-Feb-12
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.