CVE-2021-37740 : What You Need to Know

A denial of service vulnerability exists in MDT's firmware for the KNXnet/IP Secure router SCN-IP100.03 and KNX IP interface SCN-IP000.03 before v3.0.4, allowing a remote attacker to render the device unresponsive on the KNXnet/IP Secure layer.

Understanding CVE-2021-37740

This CVE highlights a denial of service vulnerability in MDT's firmware for specific device models.

What is CVE-2021-37740?

CVE-2021-37740 identifies a flaw in MDT's firmware for certain devices, enabling a remote attacker to disrupt device functionality.

The Impact of CVE-2021-37740

The vulnerability permits a malicious actor to cause the affected devices to become unresponsive, affecting their normal operations until rebooted.

Technical Details of CVE-2021-37740

This section provides insights into the technical aspects of the vulnerability.

Vulnerability Description

The issue arises from the handling of SESSION_REQUEST frames, allowing attackers to manipulate the total length field and trigger unresponsiveness.

Affected Systems and Versions

MDT's firmware versions before v3.0.4 for the KNXnet/IP Secure router SCN-IP100.03 and KNX IP interface SCN-IP000.03 are impacted.

Exploitation Mechanism

Remote attackers can exploit this vulnerability by sending a crafted SESSION_REQUEST frame with a modified total length field, causing the device to stop responding.

Mitigation and Prevention

Explore the steps to mitigate the risks associated with CVE-2021-37740.

Immediate Steps to Take

It is recommended to update affected devices to firmware version v3.0.4 or newer to address the vulnerability and enhance device security.

Long-Term Security Practices

Implementing network segmentation and access controls can help reduce the attack surface and mitigate potential risks.

Patching and Updates

Regularly monitor for firmware updates from MDT and promptly apply patches to ensure devices are protected against known vulnerabilities.