CVE-2023-35921 Explained : Impact and Mitigation

A vulnerability has been identified in SIMATIC MV540 H, SIMATIC MV540 S, SIMATIC MV550 H, SIMATIC MV550 S, SIMATIC MV560 U, and SIMATIC MV560 X devices. An unauthenticated remote attacker could exploit this flaw to cause a denial of service condition.

Understanding CVE-2023-35921

This section will cover the details, impact, technical description, affected systems, exploitation mechanism, mitigation, and prevention strategies related to CVE-2023-35921.

What is CVE-2023-35921?

CVE-2023-35921 is a vulnerability found in Siemens SIMATIC MV series devices, specifically affecting versions lower than V3.3.4. These devices are unable to process certain Ethernet frames correctly, leading to a potential denial of service if manipulated by a remote attacker. The issue necessitates manual device restarts.

The Impact of CVE-2023-35921

The impact of this vulnerability is rated as HIGH, with a CVSS v3.1 base score of 7.5. It poses a significant risk as it can be exploited remotely without authentication to disrupt the affected devices' functionality.

Technical Details of CVE-2023-35921

Let's delve into the specifics of this CVE, including the vulnerability description, affected systems and versions, and the exploitation mechanism.

Vulnerability Description

The vulnerability in CVE-2023-35921 arises from the devices' inability to handle specially crafted Ethernet frames correctly, potentially leading to a denial of service condition when triggered by an unauthorized remote attacker.

Affected Systems and Versions

Siemens SIMATIC MV540 H, SIMATIC MV540 S, SIMATIC MV550 H, SIMATIC MV550 S, SIMATIC MV560 U, and SIMATIC MV560 X devices running versions below V3.3.4 are impacted by this vulnerability.

Exploitation Mechanism

An unauthenticated remote attacker can exploit this vulnerability by sending specifically crafted Ethernet frames to the affected devices, triggering a denial of service condition that requires manual restarts.

Mitigation and Prevention

Discover the steps to mitigate the risk posed by CVE-2023-35921 and safeguard your systems from potential exploitation.

Immediate Steps to Take

Immediate actions should include implementing recommended patches, updating affected devices to secure versions, and monitoring network traffic for any signs of exploitation.

Long-Term Security Practices

Long-term strategies involve regular security audits, employee training on identifying phishing attempts, and maintaining up-to-date cybersecurity measures to prevent future vulnerabilities.

Patching and Updates

To address CVE-2023-35921, Siemens may release patches or updates that mitigate the vulnerability. Ensure timely application of these security fixes to protect your systems.