Cisco Meraki MX/Meraki Z AnyConnect VPN Server race condition

Summaryinfo

A vulnerability, which was classified as problematic, was found in Cisco Meraki MX and Meraki Z. This vulnerability affects unknown code of the component AnyConnect VPN Server. Executing a manipulation can lead to race condition. This vulnerability is handled as CVE-2024-20509. The attack can be executed remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Cisco Meraki MX and Meraki Z (affected version not known). It has been declared as problematic. This vulnerability affects some unknown functionality of the component AnyConnect VPN Server. The manipulation with an unknown input leads to a race condition vulnerability. The CWE definition for the vulnerability is CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. As an impact it is known to affect availability. CVE summarizes:

A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to hijack an AnyConnect VPN session or cause a denial of service (DoS) condition for individual users of the AnyConnect VPN service on an affected device. This vulnerability is due to weak entropy for handlers that are used during the VPN authentication process as well as a race condition that exists in the same process. An attacker could exploit this vulnerability by correctly guessing an authentication handler and then sending crafted HTTPS requests to an affected device. A successful exploit could allow the attacker to take over the AnyConnect VPN session from a target user or prevent the target user from establishing an AnyConnect VPN session with the affected device.

The advisory is available at sec.cloudapps.cisco.com. This vulnerability was named CVE-2024-20509 since 11/08/2023. The exploitation appears to be difficult. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available.

The vulnerability scanner Nessus provides a plugin with the ID 241197 (Cisco Meraki 16.2 / 17 / 18.1 < 18.1.07.13 / 18.2 < 18.2.11.3 DoS (cisco-sa-meraki-mx-vpn-dos-by-QWUkqV7X)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (241197). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• Cisco

Name

• Meraki MX
• Meraki Z

License

• commercial

Website

• Vendor: https://www.cisco.com/

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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