Cisco has updated this alert to indicate the availability of software updates.
A vulnerability in the WebVPN login page of Cisco Adaptive Security
Appliance (ASA) Software could allow an unauthenticated, remote attacker
to conduct a cross-site scripting (XSS) attack against a user of WebVPN
on the Cisco ASA.
The vulnerability is due to insufficient input
validation of a parameter. An attacker could exploit this vulnerability
by convincing a user to access a malicious link.
Cisco PSIRT would like to thank Piotr Karolak of Trustwave's SpiderLabs for reporting this vulnerability.
Cisco has confirmed the vulnerability and released software updates.
Cisco ASA Software versions 8.4(7) and prior and 9.1(4) and prior are vulnerable.
To exploit the vulnerability, the attacker may provide a link that directs a user to a malicious site and use misleading language or instructions to persuade the user to follow the provided link.
Cisco indicates through the CVSS score that proof-of-concept exploit code exists; however, the code is not known to be publicly available.
Customers are advised to consult Cisco bug ID CSCun19025 for a complete list of affected and fixed product versions.
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary script code in the user's browser session and steal sensitive information, such as authentication cookies or recently submitted data.
The vulnerability is due to insufficient input validation of a parameter by the affected software.
An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to access a malicious link. If successful, the attacker could execute arbitrary script code in the user's browser session and steal sensitive information, such as authentication cookies.
Administrators are advised to apply the appropriate updates.
Users are advised not to open email messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in email messages are safe, they are advised not to open them.
Administrators are advised to monitor affected systems.
Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at firstname.lastname@example.org.
Version 1, March 19, 2014, 11:32 AM: Cisco Adaptive Security Appliance Software contains a vulnerability that could allow an unauthenticated, remote attacker to conduct cross-site scripting attacks. Updates are not available.
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.