CVE-2001-0903 in High-bandwidth Digital Content Protection
Summary
by MITRE
Linear key exchange process in High-bandwidth Digital Content Protection (HDCP) System allows remote attackers to access data as plaintext, avoid device blacklists, clone devices, and create new device keyvectors by computing and using alternate key combinations for authentication.
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Analysis
by VulDB Data Team • 10/21/2024
The vulnerability identified as CVE-2001-0903 resides within the High-bandwidth Digital Content Protection HDCP system, a critical security protocol designed to prevent unauthorized copying of digital audio and video content as it travels between devices over digital interfaces. This weakness specifically targets the linear key exchange process that forms the foundation of HDCP's authentication mechanism, creating a fundamental flaw that undermines the entire security architecture. The vulnerability affects the cryptographic handshake between source and sink devices in digital content transmission pathways, particularly impacting HDMI and other digital display interfaces that rely on HDCP for content protection.
The technical flaw manifests in the deterministic nature of the HDCP key derivation process, where the linear mathematical relationships between key components can be exploited through reverse engineering techniques. Attackers can leverage known plaintext attacks and mathematical analysis to compute alternative key combinations that satisfy the authentication requirements without possessing the legitimate device keys. This weakness stems from the absence of sufficient entropy and randomness in the key generation algorithm, allowing malicious actors to perform brute force computations or utilize precomputed tables to derive valid key vectors. The vulnerability operates at the cryptographic protocol level, specifically targeting the HDCP v1.0 and v1.1 implementations where the key exchange mechanism lacks proper cryptographic strengthening measures.
The operational impact of this vulnerability extends far beyond simple content piracy, creating significant risks for digital content providers and device manufacturers. Remote attackers can access protected digital content in plaintext format without detection, effectively nullifying the content protection measures that HDCP was designed to enforce. Device blacklisting mechanisms become ineffective as attackers can compute and deploy alternate key combinations that bypass the legitimate device verification process. The ability to clone HDCP-enabled devices creates a proliferation of unauthorized devices that can seamlessly integrate into protected networks, while the creation of new device key vectors allows attackers to generate unlimited valid authentication tokens for any supported device type. This vulnerability compromises the integrity of the entire HDCP ecosystem and undermines trust in digital rights management systems.
Mitigation strategies for CVE-2001-0903 require immediate implementation of protocol upgrades and cryptographic improvements. Organizations should transition to HDCP v2.2 or later versions that incorporate stronger key derivation functions and non-linear authentication mechanisms. Device manufacturers must implement proper key management practices and cryptographic randomization to prevent predictable key generation patterns. Network administrators should monitor for unauthorized HDCP device connections and implement device authentication verification protocols. The vulnerability aligns with CWE-327, which addresses the use of weak cryptographic algorithms, and maps to ATT&CK technique T1552.001 for unsecured credentials. Security patches should include cryptographic strengthening measures such as the implementation of proper key derivation functions with sufficient entropy, and the adoption of non-linear key exchange protocols that prevent mathematical reverse engineering. Organizations should also consider implementing network segmentation and content monitoring solutions to detect unauthorized content access attempts. The remediation process requires comprehensive testing of updated HDCP implementations to ensure that the new cryptographic mechanisms provide adequate protection against similar vulnerabilities while maintaining compatibility with existing digital content delivery infrastructure.