A recently discovered vulnerability with the identifier CVE-2024-20402 affects the SSL VPN feature in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software. This vulnerability opens the door to a Denial of Service (DoS) attack that could be exploited by an unauthenticated, remote attacker causing the affected device to reload unexpectedly.

Vulnerability Details

This vulnerability arises due to a logic error in memory management when the device is handling SSL VPN connections. A remote attacker could exploit this vulnerability by sending specially crafted SSL/TLS packets to the SSL VPN server of the affected device. A successful exploit would enable the attacker to cause the device to reload and create a DoS condition, leading to disruptions in the normal functioning of the device.

The following code snippet demonstrates how an attacker might target vulnerable devices

import socket

def attack(ip, port):
    crafted_packet = <INSERT CRAFTED PACKET HERE>
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.connect((ip, port))
        s.sendall(crafted_packet)
        s.close()

Cisco Firepower Threat Defense (FTD) Software versions 6. and later

For more information and to see if your specific hardware and software are affected, please consult Cisco's official advisory: Link to Cisco Advisory

Exploit Mitigation & Solutions

Cisco has released software updates that address this vulnerability. Customers using affected software versions are encouraged to update their software to the latest version available. No workaround exists for this vulnerability.

Download and install the appropriate patch for your specific hardware and software setup from Cisco's official downloads page: Link to Cisco Downloads

Conclusion

To protect your network and devices from this DoS vulnerability (CVE-2024-20402) in the SSL VPN feature for Cisco ASA and FTD Software, it is crucial to apply the appropriate patches and updates provided by Cisco. Keep in mind that unauthenticated, remote attackers can exploit this vulnerability and cause significant disruptions. Always prioritize maintaining your software with the latest security updates and remain vigilant to avoid future vulnerabilities.

Timeline

Published on: 10/23/2024 18:15:07 UTC
Last modified on: 10/25/2024 12:56:36 UTC