CVE-2021-33538 : Security Advisory and Response

In Weidmüller Industrial WLAN devices in multiple versions, there exists an exploitable improper access control vulnerability that allows for the overwrite of an existing user account password. This vulnerability can result in remote shell access to the device as that user, enabling an attacker to send commands while authenticated as a low privilege user.

Understanding CVE-2021-33538

This CVE identifies a critical security issue in Weidmüller Industrial WLAN devices, impacting specific versions and configurations.

What is CVE-2021-33538?

The CVE-2021-33538 vulnerability is related to improper access control in Weidmüller Industrial WLAN devices, allowing attackers to gain unauthorized access and potentially take control of the affected devices.

The Impact of CVE-2021-33538

The impact of CVE-2021-33538 is rated as high, with a base score of 8.8 and the potential for remote shell access and unauthorized command execution.

Technical Details of CVE-2021-33538

The technical details of CVE-2021-33538 shed light on the vulnerability, affected systems, and the exploitation mechanism.

Vulnerability Description

The vulnerability stems from an improper access control issue in the iw_webs account settings functionality, enabling attackers to overwrite existing user account passwords.

Affected Systems and Versions

The vulnerability affects specific versions of Weidmüller Industrial WLAN devices, including IE-WL(T)-BL-AP-CL-XX and IE-WL(T)-VL-AP-CL-XX.

Exploitation Mechanism

Exploiting CVE-2021-33538 involves crafting a malicious user name entry to trigger the overwrite of a user account password and gain remote shell access.

Mitigation and Prevention

To address CVE-2021-33538, immediate steps, long-term security practices, and the importance of applying patches and updates are essential.

Immediate Steps to Take

Users should update affected devices to the fixed versions promptly to mitigate the risk of exploitation.

Long-Term Security Practices

Implementing robust access control measures and regular security assessments can enhance the overall security posture against such vulnerabilities.

Patching and Updates

Weidmüller has released fixed versions for the affected devices. Users are advised to install IE-WL(T)-BL-AP-CL-XX versions V1.16.21 (Build 21010513) or later, and IE-WL(T)-VL-AP-CL-XX versions V1.11.13 (Build 21010513) or later.