Microsoft Defender for IoT Remote Code Execution Vulnerability

Vulnerability

CVE-2021-43882 is a remote code execution vulnerability in Microsoft Defender for IoT (also known as Azure Defender for IoT). The flaw resides in the password reset mechanism of both the management console and sensor appliances. The issue stems from improper validation of a certificate chain during the reset process, allowing an unauthenticated attacker to bypass authentication. This affects all versions of Microsoft Defender for IoT prior to the fix released in December 2021. [1]

Exploitation

An attacker can exploit this vulnerability remotely over the network without authentication or any special privileges. The attack requires no user interaction. The attacker sends a crafted request to the password reset endpoint, where the lack of proper certificate chain validation enables the attacker to assume an authenticated identity. [1]

Impact

Successful exploitation allows the attacker to bypass authentication entirely, gaining administrative-level access to the Defender for IoT console or sensor. This leads to full compromise of confidentiality, integrity, and availability, as the attacker can execute arbitrary code, modify system configurations, and access sensitive data. [1]

Mitigation

Microsoft released a security update for Defender for IoT on December 14, 2021, which addresses this vulnerability by improving certificate validation. Users should apply the update immediately. No workarounds are available. The vulnerability is not currently listed on CISA's Known Exploited Vulnerabilities (KEV) catalog. [1]