CVE-2021-33737 : Vulnerability Insights and Analysis

A vulnerability has been identified in SIMATIC CP 343-1 (incl. SIPLUS variants), SIMATIC CP 343-1 Advanced, SIMATIC CP 343-1 ERPC, SIMATIC CP 343-1 Lean (incl. SIPLUS variants), SIMATIC CP 443-1 (versions < V3.3), SIMATIC CP 443-1 Advanced, SIPLUS NET CP 443-1, and SIPLUS NET CP 443-1 Advanced devices. Sending a specially crafted packet to port 102/tcp could result in a denial of service condition, requiring a restart to restore normal operations.

Understanding CVE-2021-33737

This section provides insights into the impact, technical details, and mitigation strategies related to CVE-2021-33737.

What is CVE-2021-33737?

CVE-2021-33737 is a vulnerability in various Siemens SIMATIC devices that can be exploited by sending a malicious packet to trigger a denial of service condition.

The Impact of CVE-2021-33737

The vulnerability can lead to a denial of service state on the affected devices, disrupting their normal operations until a restart is performed.

Technical Details of CVE-2021-33737

Explore the specific details regarding the vulnerability, affected systems, and the exploitation mechanism.

Vulnerability Description

This vulnerability, classified under CWE-119, involves improper restriction of operations within the bounds of a memory buffer, allowing for unauthorized disruption through specially crafted packets.

Affected Systems and Versions

Siemens SIMATIC CP 343-1, CP 343-1 Advanced, CP 343-1 ERPC, CP 343-1 Lean, CP 443-1, CP 443-1 Advanced, SIPLUS NET CP 443-1, and SIPLUS NET CP 443-1 Advanced devices are affected by this vulnerability.

Exploitation Mechanism

Exploiting this vulnerability involves sending a carefully crafted packet to port 102/tcp on the targeted devices to trigger the denial of service condition.

Mitigation and Prevention

Understand the immediate steps and long-term security practices to mitigate the risks associated with CVE-2021-33737.

Immediate Steps to Take

It is advised to apply vendor-recommended patches and configurations to protect the affected devices from exploitation. Network segmentation and access control lists can also limit exposure.

Long-Term Security Practices

Implementing regular security updates, conducting security assessments, and monitoring network traffic for suspicious activities can enhance the overall security posture.

Patching and Updates

Stay informed about security bulletins and updates provided by Siemens to apply necessary patches and configurations promptly.