Cisco ASA/Firepower Threat Defense Software SSL VPN access of memory location after end of buffer

Summaryinfo

A vulnerability was found in Cisco ASA and Firepower Threat Defense Software. It has been classified as problematic. This issue affects some unknown processing of the component SSL VPN. The manipulation leads to access of memory location after end of buffer. This vulnerability is referenced as CVE-2024-20402. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Cisco ASA and Firepower Threat Defense Software (unknown version) and classified as critical. This issue affects an unknown code block of the component SSL VPN. The manipulation with an unknown input leads to a access of memory location after end of buffer vulnerability. Using CWE to declare the problem leads to CWE-788. The product reads or writes to a buffer using an index or pointer that references a memory location after the end of the buffer. Impacted is availability. The summary by CVE is:

A vulnerability in the SSL VPN feature for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to a logic error in memory management when the device is handling SSL VPN connections. An attacker could exploit this vulnerability by sending crafted SSL/TLS packets to the SSL VPN server of the affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

It is possible to read the advisory at sec.cloudapps.cisco.com. The identification of this vulnerability is CVE-2024-20402 since 11/08/2023. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/15/2025).

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Firewall Software

Vendor

• Cisco

Name

• ASA
• Firepower Threat Defense Software

License

• commercial

Website

• Vendor: https://www.cisco.com/

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