CVE-2021-33535 : What You Need to Know

This CVE-2021-33535 vulnerability affects Weidmüller Industrial WLAN devices, specifically in multiple versions. In the affected devices, there exists an exploitable format string vulnerability that could lead to remote code execution. Here's what you need to know about CVE-2021-33535.

Understanding CVE-2021-33535

In this section, we will delve into what CVE-2021-33535 entails.

What is CVE-2021-33535?

A format string vulnerability exists in the iw_console conio_writestr functionality of Weidmüller Industrial WLAN devices. An attacker can exploit this vulnerability using a specially crafted time server entry, causing a buffer overflow and enabling remote code execution.

The Impact of CVE-2021-33535

The impact of this vulnerability is rated as HIGH, with a CVSS base score of 8.8. It poses risks to confidentiality, integrity, and availability, requiring low privileges for exploitation.

Technical Details of CVE-2021-33535

Let's dive into the technical aspects of CVE-2021-33535.

Vulnerability Description

The vulnerability arises from a format string issue in the iw_console conio_writestr functionality of the affected WLAN devices, allowing an attacker to execute arbitrary code remotely.

Affected Systems and Versions

Weidmüller Industrial WLAN devices with specific versions are impacted by this vulnerability, including IE-WL(T)-BL-AP-CL-XX and IE-WL(T)-VL-AP-CL-XX.

Exploitation Mechanism

By sending specially crafted commands disguised as a low privilege user, an attacker can trigger the format string vulnerability, enabling remote code execution.

Mitigation and Prevention

Here, we discuss the steps to mitigate and prevent exploits related to CVE-2021-33535.

Immediate Steps to Take

Users should update affected devices to the fixed versions immediately. For IE-WL(T)-BL-AP-CL-XX, version V1.16.21 (Build 21010513) and above are secure. For IE-WL(T)-VL-AP-CL-XX, version V1.11.13 (Build 21010513) and higher are safe.

Long-Term Security Practices

Implementing network segmentation, regularly monitoring device logs, and conducting security training for personnel can enhance long-term security resilience against such vulnerabilities.

Patching and Updates

Regularly apply security patches provided by Weidmüller for Industrial WLAN devices to mitigate the risks associated with CVE-2021-33535.