Cisco Firewall Services Module (FWSM) and Cisco Adaptive Security Appliance (ASA) Software contain a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
The IKE version 1 implementation contains a vulnerability that could allow an unauthenticated, remote attacker to cause a reload of an affected device.
The vulnerability is due to the incorrect processing of an incoming IKE version 1 message. An attacker could exploit this vulnerability by sending a crafted IKE message. An exploit could allow the attacker to cause a reload of an affected device.
Cisco has confirmed the vulnerability in a security advisory and released software updates.
The following releases of Cisco FWSM are vulnerable when running on Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers when IKE version 1 is enabled:
Cisco FWSM Releases prior to 3.2(24.1)
Cisco FWSM Releases prior to 4.1(11.1)
The following releases of Cisco ASA Software are also affected by this vulnerability:
Cisco ASA Releases prior to 7.2(5.10)
Cisco ASA Releases prior to 8.0(5.28)
Cisco ASA Releases prior to 8.2(5.35)
Cisco ASA Releases prior to 8.3(2.34)
Cisco ASA Releases prior to 8.4(4.11)
Cisco ASA Releases prior to 8.6(1.10)
Cisco ASA Releases prior to 8.7(1.3)
To exploit this vulnerability, an attacker would need access to an internal network to send crafted IKE messages to a vulnerable device. In a typical network configuration, such devices are placed on trusted, internal networks. This access requirement could limit the possibility of a successful exploit.
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 the targeted device to reload, resulting in a denial of service (DoS) condition. Repeated exploitation could result in a sustained DoS condition.
The vulnerability is due to incorrect processing of an incoming IKE version 1 message by an affected device. The vulnerability affects routed firewall mode in both single and multi-context mode. In addition, the vulnerability can be triggered by IP version 4 or IP version 6 traffic.
An unauthenticated, remote attacker could exploit this vulnerability by sending a crafted IKE message to the affected device. If successful, the attacker could cause the device to reload, resulting in a DoS condition.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators may consider disabling VPN access for administration and use SSH or HTTPS for administration.
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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