CVE-2019-10122 in Homematic CCU2
Summary
by MITRE
eQ-3 HomeMatic CCU2 devices before 2.41.9 and CCU3 devices before 3.43.16 have buffer overflows in the ReGa ise GmbH HTTP-Server 2.0 component, aka HMCCU-179. This may lead to remote code execution.
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Analysis
by VulDB Data Team • 10/24/2023
The vulnerability identified as CVE-2019-10122 affects eQ-3 HomeMatic CCU2 and CCU3 home automation devices, representing a critical buffer overflow flaw within the ReGa ise GmbH HTTP-Server 2.0 component. This issue impacts firmware versions prior to 2.41.9 for CCU2 devices and 3.43.16 for CCU3 devices, creating a significant security risk for users of these smart home systems. The vulnerability resides in the web server implementation that handles HTTP requests, making it accessible through network-based attacks targeting the device's web interface.
The technical flaw manifests as a classic buffer overflow condition within the HTTP server component, where insufficient input validation allows attackers to craft malicious HTTP requests that exceed allocated buffer boundaries. This memory corruption vulnerability occurs when the server processes specially crafted payloads through its web interface, potentially allowing attackers to overwrite adjacent memory locations. The buffer overflow can be exploited remotely without requiring authentication, making it particularly dangerous in network-connected environments where these devices are accessible from the internet.
The operational impact of this vulnerability extends beyond simple remote code execution, as it fundamentally compromises the security posture of affected HomeMatic systems. Attackers who successfully exploit this vulnerability can gain unauthorized control over the affected devices, potentially leading to complete system compromise and unauthorized access to connected home automation components. The implications include the ability to manipulate smart home devices, access sensitive configuration data, and potentially use the compromised devices as launch points for further attacks within the local network. This vulnerability directly violates the principle of least privilege and can enable lateral movement within home automation ecosystems.
Mitigation strategies for CVE-2019-10122 focus primarily on firmware updates to the affected versions, with eQ-3 releasing patches addressing the buffer overflow conditions in their respective device firmware. Network segmentation and firewall rules should be implemented to restrict access to the affected devices, particularly limiting external exposure of the web interfaces. Additionally, organizations and individuals should conduct thorough inventory assessments to identify all affected HomeMatic devices within their environments. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and maps to ATT&CK techniques involving remote code execution and privilege escalation through unpatched network services. Security monitoring should include detection of anomalous HTTP traffic patterns that might indicate exploitation attempts against the vulnerable web server component.