Cisco Firewall Services Module Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
Cisco Firewall Services Module (FWSM) for the Cisco Catalyst 6500 Series switches and Cisco 7600 Series routers that use Cisco Firewall Services Module Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
The vulnerability is due to the exhaustion of resources on a targeted device when handling multiple requests. An unauthenticated, remote attacker could exploit this vulnerability to by sending a large number of requests to the device, causing the device to reload and leading to a DoS condition.
Cisco has confirmed this vulnerability in a security advisory and has released updated software.
Cisco Firewall Services Module Software releases prior to the following are vulnerable:
It is likely that an attacker would need to have access to an internal, private network to send a high number of network access authentication requests. This requirement could limit the possibility of a potential attack.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
An unauthenticated, remote attacker could exploit this vulnerability to cause a targeted device to reload, resulting in a DoS condition. Repeated attacks could result in a sustained DoS condition.
The vulnerability is due to the exhaustion of resources when the device tries to process a high number of network access authentication requests.
An unauthenticated, remote attacker could exploit this vulnerability by sending a high number of network access authentication requests to a device that is running a version of the affected software. If successful, the attacker could cause a DoS condition by having the device reload. If the attacks are repeated, a sustained DoS condition may occur.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators are advised to implement an intrusion prevention system (IPS) or intrusion detection system (IDS) to help detect and prevent attacks that attempt to exploit this vulnerability.
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 e-mail at email@example.com.
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