CVE-2019-10121 Explained : Impact and Mitigation

A security flaw in eQ-3 HomeMatic CCU2 and CCU3 devices prior to specific versions allows unauthorized access as an admin user.

Understanding CVE-2019-10121

What is CVE-2019-10121?

eQ-3 HomeMatic CCU2 devices before version 2.41.8 and CCU3 devices before version 3.43.15 have a vulnerability related to authentication, enabling attackers to gain unauthorized access.

The Impact of CVE-2019-10121

The vulnerability allows attackers to bypass authorization checks and log in as admin users, potentially leading to unauthorized system control and data compromise.

Technical Details of CVE-2019-10121

Vulnerability Description

The flaw arises from the use of session IDs for authentication without proper authorization verification, enabling attackers to exploit the HMCCU-153 dialogue to acquire session IDs.

Affected Systems and Versions

eQ-3 HomeMatic CCU2 devices before version 2.41.8
eQ-3 HomeMatic CCU3 devices before version 3.43.15

Exploitation Mechanism

Attackers can acquire session IDs through the user authentication dialogue, HMCCU-153, to gain unauthorized admin access.

Mitigation and Prevention

Immediate Steps to Take

Update eQ-3 HomeMatic CCU2 devices to version 2.41.8 or later
Update eQ-3 HomeMatic CCU3 devices to version 3.43.15 or later
Monitor for any unauthorized access or suspicious activities

Long-Term Security Practices

Implement multi-factor authentication for enhanced security
Regularly review and update authentication mechanisms

Patching and Updates

Apply security patches promptly
Stay informed about security advisories and updates from eQ-3