CVE-2019-14985 in Homematic CCU2
Summary
by MITRE
eQ-3 Homematic CCU2 and CCU3 with the CUxD AddOn installed allow Remote Code Execution by unauthenticated attackers with access to the web interface, because this interface can access the CMD_EXEC virtual device type 28.
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Analysis
by VulDB Data Team • 11/25/2023
The vulnerability identified as CVE-2019-14985 affects eQ-3 Homematic Central Control Units CCU2 and CCU3 when equipped with the CUxD AddOn component. This represents a critical security flaw that enables unauthenticated remote code execution through the web interface, fundamentally compromising the integrity and security posture of these home automation systems. The vulnerability stems from the improper access controls within the web interface implementation, specifically allowing arbitrary command execution through the CMD_EXEC virtual device type 28.
The technical flaw manifests through the CUxD AddOn's web interface implementation which fails to properly validate or restrict access to the CMD_EXEC virtual device type. This virtual device type operates as a command execution interface that allows arbitrary system commands to be executed without proper authentication. The vulnerability exists because the web interface does not enforce access controls or authentication mechanisms before allowing access to this command execution capability. Attackers can directly invoke this functionality through web requests without requiring valid credentials, effectively bypassing all authentication mechanisms that should normally protect such sensitive operations.
The operational impact of this vulnerability is severe and far-reaching for affected systems. An unauthenticated attacker who gains access to the web interface can execute arbitrary commands with the privileges of the web server process, typically running with elevated system permissions. This allows for complete system compromise including but not limited to data exfiltration, system modification, persistence mechanisms installation, and potential lateral movement within network environments where these devices are deployed. The vulnerability affects both CCU2 and CCU3 models, indicating a widespread issue across the affected product line and potentially impacting numerous home automation installations globally.
The vulnerability aligns with CWE-284 (Improper Access Control) and represents a classic example of insufficient authorization checks in web applications. From an attack framework perspective, this vulnerability maps directly to ATT&CK technique T1059.001 (Command and Scripting Interpreter: PowerShell) and T1059.007 (Command and Scripting Interpreter: JavaScript) as attackers can leverage the command execution capability to run malicious payloads. The lack of authentication requirements for command execution creates an immediate path to system compromise that bypasses traditional network security controls. Organizations should consider implementing network segmentation and access control measures to limit exposure, while also applying vendor-provided patches or firmware updates when available. The vulnerability demonstrates the critical importance of proper input validation and access control implementation in web-based management interfaces, particularly in IoT and home automation systems where physical access may be limited but network exposure remains high.