CVE-2013-6952 in WeMo
Summary
by MITRE
The Belkin WeMo Home Automation firmware before 3949 has a hardcoded GPG key, which makes it easier for remote attackers to spoof firmware updates and execute arbitrary code via crafted signed data.
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Analysis
by VulDB Data Team • 08/17/2024
The vulnerability identified as CVE-2013-6952 resides within the Belkin WeMo Home Automation firmware ecosystem, specifically affecting versions prior to 3949. This security flaw represents a critical weakness in the device's firmware update mechanism that fundamentally undermines the integrity of the entire home automation system. The issue stems from the inclusion of a hardcoded GPG key within the firmware, a design decision that creates a persistent security vulnerability across all affected devices. This hardcoded cryptographic key serves as a universal signing mechanism that allows unauthorized parties to generate valid signatures for malicious firmware updates, effectively bypassing the intended security controls that protect against unauthorized modifications.
The technical implementation of this vulnerability manifests through the use of a static cryptographic key that remains unchanged across all devices and firmware versions. This hardcoded key, which is embedded within the firmware binary during the development process, provides attackers with a consistent method to forge legitimate update signatures. When the WeMo devices attempt to validate firmware updates, they rely on this predetermined key to verify authenticity, creating a scenario where any attacker possessing the key can generate spoofed update packages that will be accepted as legitimate by the device. The flaw operates at the core of the firmware update validation process, where the security model assumes that the private key used for signing updates remains secret and is not embedded within the firmware itself.
From an operational perspective, this vulnerability creates a significant attack surface that enables remote code execution capabilities for threat actors. The implications extend beyond simple firmware manipulation to encompass complete system compromise, as attackers can potentially execute arbitrary code on affected devices through the spoofed update mechanism. This vulnerability directly impacts the security posture of home networks by allowing attackers to gain control over smart home devices, potentially leading to unauthorized access to connected systems, data exfiltration, or use of compromised devices as entry points for broader network attacks. The remote nature of the attack means that adversaries do not require physical access to devices, making the vulnerability particularly concerning for IoT deployments where devices are often left exposed to untrusted network environments.
The security implications of this vulnerability align with multiple ATT&CK framework techniques including T1059 for command and script interpreter execution and T1071 for application layer protocol usage. From a CWE perspective, this represents a variant of CWE-310 which addresses cryptographic weaknesses, specifically focusing on the improper use of cryptographic keys. The vulnerability also demonstrates characteristics of CWE-259, which deals with hard-coded passwords and keys, and CWE-320, which addresses weaknesses in key management. Organizations and users should immediately implement mitigation strategies including firmware updates to version 3949 or later, network segmentation to limit device exposure, and monitoring for unauthorized firmware update activities. The remediation process requires not only updating the firmware but also implementing network-based controls to prevent unauthorized communication with the devices, as the hardcoded key vulnerability cannot be patched without a firmware update that removes the embedded key and replaces it with a secure, dynamic key management approach.