CVE-2021-22699 : Exploit Details and Defense Strategies

A detailed analysis of CVE-2021-22699, highlighting the vulnerability in Modicon M241/M251 logic controllers firmware.

Understanding CVE-2021-22699

This section provides insights into the vulnerability, its impact, technical details, and mitigation strategies.

What is CVE-2021-22699?

CVE-2021-22699 is an Improper Input Validation vulnerability found in Modicon M241/M251 logic controllers firmware versions prior to V5.1.9.1. It can lead to denial of service attacks when specially crafted requests are sent over HTTP.

The Impact of CVE-2021-22699

This vulnerability allows attackers to disrupt the normal operation of affected controllers, potentially causing downtime or system unavailability.

Technical Details of CVE-2021-22699

In this section, we delve into the specifics of the vulnerability, including the description, affected systems, and exploitation mechanism.

Vulnerability Description

The vulnerability arises due to insufficient input validation in the firmware of Modicon M241/M251 logic controllers, enabling malicious actors to trigger denial of service by sending specific malicious requests.

Affected Systems and Versions

Modicon M241/M251 logic controllers firmware versions prior to V5.1.9.1 are susceptible to this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting and sending malicious requests to the controller over HTTP, leading to service disruption.

Mitigation and Prevention

This section outlines the steps to mitigate the CVE-2021-22699 vulnerability and prevent potential exploitation.

Immediate Steps to Take

Immediately upgrade affected systems to firmware version V5.1.9.1 or above to patch the vulnerability and prevent possible attacks.

Long-Term Security Practices

Implement robust input validation mechanisms, network segmentation, and regular security updates to enhance overall system security.

Patching and Updates

Regularly check for firmware updates and security advisories from the vendor to apply patches promptly and strengthen the security posture of the systems.