CVE-2021-25664 : Exploit Details and Defense Strategies

A vulnerability has been identified in multiple Siemens products, including Capital VSTAR, Nucleus NET, Nucleus ReadyStart V3, Nucleus ReadyStart V4, and Nucleus Source Code. The vulnerability exists in the function processing the Hop-by-Hop extension header in IPv6 packets, allowing attackers to create an infinite loop.

Understanding CVE-2021-25664

This section delves into the details of the CVE-2021-25664 vulnerability, affecting various Siemens products.

What is CVE-2021-25664?

CVE-2021-25664 is a vulnerability present in Siemens products, enabling attackers to manipulate the length field of the Hop-by-Hop extension header in IPv6 packets, potentially triggering an infinite loop in the affected systems.

The Impact of CVE-2021-25664

The vulnerability poses a significant risk as attackers could exploit it to disrupt the affected systems by causing an infinite loop, potentially leading to denial of service conditions or other malicious activities.

Technical Details of CVE-2021-25664

This section explores the technical aspects of the CVE-2021-25664 vulnerability in Siemens products.

Vulnerability Description

The flaw arises from the lack of length field checks in the function responsible for processing the Hop-by-Hop extension header in IPv6 packets, allowing threat actors to induce an infinite loop through arbitrary length values.

Affected Systems and Versions

Impacted Siemens products include Capital VSTAR (Versions including affected IPv6 stack), Nucleus NET (All versions), Nucleus ReadyStart V3 (All versions < V2017.02.4), Nucleus ReadyStart V4 (All versions < V4.1.0), and Nucleus Source Code (Versions including affected IPv6 stack).

Exploitation Mechanism

The vulnerability can be exploited by manipulating the length field of the Hop-by-Hop extension header in IPv6 packets, causing the affected function to enter an infinite loop.

Mitigation and Prevention

In this section, we discuss the steps to mitigate and prevent the exploitation of CVE-2021-25664 in Siemens products.

Immediate Steps to Take

Organizations using the affected Siemens products should apply security patches provided by the vendor promptly. Monitoring network traffic for any signs of exploitation is also crucial to detect potential attacks.

Long-Term Security Practices

Implementing network segmentation, access controls, and regular security audits can enhance the overall security posture of the environment and help prevent similar vulnerabilities in the future.

Patching and Updates

Staying informed about security updates and patches released by Siemens is vital. Organizations should establish robust patch management procedures to ensure timely implementation of security fixes.