CVE-2022-20933 : Security Advisory and Response

A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z3 Teleworker Gateway devices has been identified, allowing an unauthenticated remote attacker to trigger a denial of service (DoS) condition on the affected device. This article provides an overview of CVE-2022-20933, its impact, technical details, and mitigation strategies.

Understanding CVE-2022-20933

This section delves into the key aspects of the CVE-2022-20933 vulnerability.

What is CVE-2022-20933?

The vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z3 Teleworker Gateway devices allows an unauthenticated remote attacker to create a denial of service (DoS) scenario on the device. Insufficient validation of client-supplied parameters during SSL VPN session establishment is the root cause.

The Impact of CVE-2022-20933

Exploiting this vulnerability can lead to the Cisco AnyConnect VPN server crashing and restarting, disrupting SSL VPN connections. This can compel remote users to re-establish VPN connections and re-authenticate, potentially preventing new SSL VPN connections.

Technical Details of CVE-2022-20933

This section outlines the specifics of the CVE-2022-20933 vulnerability.

Vulnerability Description

The vulnerability arises due to insufficient validation of client-supplied parameters, enabling attackers to craft malicious requests that, when sent to the device, crash the Cisco AnyConnect VPN server.

Affected Systems and Versions

Vendor: Cisco
Product: Cisco Meraki MX Firmware
Versions: n/a (affected)

Exploitation Mechanism

Attackers exploit the vulnerability by crafting and sending malicious requests to the device, causing the Cisco AnyConnect VPN server to crash, disrupting SSL VPN connections.

Mitigation and Prevention

This section provides guidance on mitigating the risks posed by CVE-2022-20933.

Immediate Steps to Take

Cisco Meraki has released software updates that address this vulnerability. It is recommended to apply these updates promptly to safeguard the affected devices.

Long-Term Security Practices

Implement robust security measures, such as regular security assessments, network segmentation, and access controls, to enhance overall cybersecurity posture.

Patching and Updates

Stay informed about security updates from Cisco Meraki and promptly apply patches to address any new vulnerabilities and ensure the security of the devices.