CVE-2021-27434 : Exploit Details and Defense Strategies

A vulnerability has been identified in OPC UA Products built with the .NET Framework 4.5, 4.0, and 3.5. The vulnerability, assigned CVE-2021-27434, allows an attacker to trigger a stack overflow through an uncontrolled recursion.

Understanding CVE-2021-27434

This section will cover the details of the vulnerability affecting OPC UA Products built with the .NET Framework.

What is CVE-2021-27434?

Products with Unified Automation .NET based OPC UA Client/Server SDK Bundle: Versions V3.0.7 and prior (.NET 4.5, 4.0, and 3.5 Framework versions only) are prone to uncontrolled recursion, enabling attackers to initiate a stack overflow.

The Impact of CVE-2021-27434

The exploit of this vulnerability could lead to a stack overflow, allowing threat actors to execute arbitrary code or crash the application.

Technical Details of CVE-2021-27434

Here we delve into the specifics of the vulnerability affecting OPC UA Products.

Vulnerability Description

The flaw in OPC UA Products allows for uncontrolled recursion, leading to a stack overflow that can be manipulated by malicious entities.

Affected Systems and Versions

Unified Automation .NET based OPC UA Client/Server SDK Bundle in versions V3.0.7 and earlier running on .NET Framework versions 4.5, 4.0, and 3.5 are impacted by this CVE.

Exploitation Mechanism

By triggering an uncontrolled recursion, threat actors can exploit the vulnerability to achieve a stack overflow, potentially causing a denial of service or execution of arbitrary code.

Mitigation and Prevention

Protecting systems against CVE-2021-27434 is crucial to maintaining security. Here's how to mitigate the risks associated with this vulnerability.

Immediate Steps to Take

Immediately updating affected versions of Unified Automation .NET based OPC UA Client/Server SDK Bundle to versions beyond V3.0.7 is essential to mitigate this vulnerability.

Long-Term Security Practices

Implementing secure coding practices, regular security audits, and monitoring for unusual behavior can enhance the long-term security posture against such vulnerabilities.

Patching and Updates

Stay informed about security patches and updates released by the vendor to address CVE-2021-27434 and other potential vulnerabilities.