CVE-2021-42020 : What You Need to Know

A vulnerability has been identified in Siemens devices including RUGGEDCOM series. The issue lies in a third-party component's TFTP functionality, leading to potential data corruption and application hard-fault.

Understanding CVE-2021-42020

This CVE affects various Siemens RUGGEDCOM devices due to improper file name handling in TFTP functionality.

What is CVE-2021-42020?

The vulnerability in the TFTP functionality of the affected devices can be exploited by an attacker to cause data corruption and potentially crash the application.

The Impact of CVE-2021-42020

Exploitation of this vulnerability could result in data corruption and potentially lead to a hard-fault of the application, impacting device functionality and stability.

Technical Details of CVE-2021-42020

The vulnerability details and how it affects the Siemens RUGGEDCOM devices.

Vulnerability Description

The issue arises from the failure to check for null terminations in file names within the TFTP functionality of the affected devices.

Affected Systems and Versions

Various RUGGEDCOM devices by Siemens are impacted, with versions < V4.3.8 or < V5.6.0 being vulnerable.

Exploitation Mechanism

By exploiting the lack of null termination checks in TFTP file names, an attacker may cause data corruption or trigger a hard-fault in the device's application.

Mitigation and Prevention

Measures to address and prevent exploitation of CVE-2021-42020.

Immediate Steps to Take

Update the affected devices to versions V4.3.8 or V5.6.0 to mitigate the vulnerability.
Implement network segmentation to minimize the attack surface and isolate critical devices.

Long-Term Security Practices

Regularly monitor for security advisories and updates from Siemens regarding device vulnerabilities.
Conduct security assessments and penetration testing to identify and address potential vulnerabilities.

Patching and Updates

Ensure timely application of security patches released by Siemens to address vulnerabilities like CVE-2021-42020.