CVE-2021-45033 : Security Advisory and Response

A vulnerability has been identified in CP-8000 MASTER MODULE WITH I/O -25/+70°C, CP-8000 MASTER MODULE WITH I/O -40/+70°C, CP-8021 MASTER MODULE, CP-8022 MASTER MODULE WITH GPRS by Siemens. An undocumented debug port uses hard-coded default credentials, potentially granting unauthorized access to an administrative debug shell.

Understanding CVE-2021-45033

What is CVE-2021-45033?

CVE-2021-45033 is a vulnerability found in several Siemens products, where an undocumented debug port with hardcoded credentials could be exploited by a knowledgeable attacker.

The Impact of CVE-2021-45033

The vulnerability allows unauthorized users to gain administrative access to the affected devices, posing a significant security risk.

Technical Details of CVE-2021-45033

Vulnerability Description

The flaw involves the presence of hard-coded credentials in the undocumented debug port of the affected Siemens devices, enabling unauthorized access.

Affected Systems and Versions

CP-8000 MASTER MODULE WITH I/O -25/+70°C: All versions < V16.20
CP-8000 MASTER MODULE WITH I/O -40/+70°C: All versions < V16.20
CP-8021 MASTER MODULE: All versions < V16.20
CP-8022 MASTER MODULE WITH GPRS: All versions < V16.20

Exploitation Mechanism

An attacker with knowledge of the hard-coded credentials can enable the debug port, allowing them to access an administrative debug shell on the affected device.

Mitigation and Prevention

Immediate Steps to Take

Disable the undocumented debug port if not required for operations
Implement network segmentation to limit access
Regularly monitor for unauthorized access attempts

Long-Term Security Practices

Conduct regular security assessments and penetration testing
Educate users on secure configuration practices

Patching and Updates

Apply the necessary patches provided by Siemens to address the vulnerability