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AV:N/AC:M/Au:N/C:N/I:P/A:N/E:POC/RL:OF/RC:C
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Cisco ASA Software versions 8.0.4(28) and prior contain a vulnerability that could allow an unauthenticated, remote attacker to conduct cross-site scripting attacks.
The vulnerability is due to insufficient input validation within the WebVPN clientless mode feature. Attackers could exploit this vulnerability to conduct cross-site scripting attacks, which could result in the execution of arbitrary HTML or scripting code in a user's browser session within the security context of the site.
Proof of concept code is available to demonstrate this cross-site scripting attack.
Cisco has confirmed the vulnerability and released software updates.
To exploit this vulnerability, the clientless mode of the WebVPN feature must be enabled. An attacker must also be able to inject crafted HTTP headers into a browser, which requires the use of a web application technology such as JavaScript or Flash. These factors reduce the likelihood of an attack.
An exploit may allow the attacker to obtain the WebVPN session cookie and gain unauthorized access to the VPN device.
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Cisco has confirmed this vulnerability in Cisco bug ID CSCsy82093. Cisco has updated this bug ID to include fixed versions of the affected software.
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Administrators are advised to apply the appropriate updates.
Administrators are advised to restrict access to affected systems to trusted users.
Users are advised not to follow unsolicited links. Users should verify the authenticity of unexpected links prior to following them.
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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 e-mail at tac@cisco.com.
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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.
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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.
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Version Description Section Status Date 1.0 Initial Release NA Final 2009-Apr-01
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