CVE-2021-27383 : Security Advisory and Response

A heap allocation leak vulnerability has been identified in several Siemens products, including SIMATIC HMI Comfort Panels and SINAMICS drives. This vulnerability could lead to a Denial-of-Service condition.

Understanding CVE-2021-27383

This CVE-2021-27383 affects various Siemens products due to a heap allocation leak vulnerability in the SmartVNC server Tight encoder.

What is CVE-2021-27383?

CVE-2021-27383 is a vulnerability present in multiple Siemens products, potentially allowing attackers to carry out a Denial-of-Service attack.

The Impact of CVE-2021-27383

The vulnerability in Siemens products can be exploited by malicious actors to trigger a Denial-of-Service condition, impacting the availability of the affected systems.

Technical Details of CVE-2021-27383

The vulnerability arises from a heap allocation leak in the server Tight encoder of SmartVNC.

Vulnerability Description

The heap allocation leak vulnerability in the affected Siemens products could be exploited by attackers for a Denial-of-Service attack.

Affected Systems and Versions

SIMATIC HMI Comfort Panels V15 and V16
SIMATIC HMI KTP Mobile Panels V15 and V16
SIMATIC WinCC Runtime Advanced V15 and V16
SINAMICS GH150, GL150, GM150, SH150, SL150, SM120, SM150, and SM150i drives

Exploitation Mechanism

The vulnerability can be exploited by attackers sending specially crafted requests to the affected products, resulting in a heap allocation leak.

Mitigation and Prevention

It is crucial to take immediate steps to mitigate the impact of CVE-2021-27383 and prevent possible attacks.

Immediate Steps to Take

Siemens recommends applying the necessary updates and patches provided by the company to address the vulnerability.
Monitor network traffic for any suspicious activity that could indicate an ongoing exploitation attempt.
Restrict network access to vulnerable products to minimize exposure to potential attacks.

Long-Term Security Practices

Regularly update and patch all Siemens products to ensure the latest security fixes are in place.
Implement network segmentation and access controls to restrict unauthorized access to critical systems.
Educate users and administrators about the importance of cybersecurity best practices to enhance overall security posture.

Patching and Updates

Siemens has released updates to address the vulnerability in the affected products. It is recommended to apply the relevant patches as soon as possible to protect the systems from potential exploitation.