HDMI-Watch: Smart Intrusion Detection System Against HDMI Attacks

The High Definition Multimedia Interface (HDMI) is the backbone and the de-facto standard for Audio/Video connections between video-enabled devices. Today, nearly ten billion HDMI devices are used to distribute A/V signals in homes, offices, concert halls, and sporting events. An important component in HDMI is the Consumer Electronics Control (CEC) protocol, which allows HDMI devices to share an HDMI distribution to communicate and interact with each other. In this work, we identify security and privacy issues in HDMI networks by taping into CEC protocol vulnerabilities, using them to implement realistic proof-of-work attacks on HDMI distribution networks. We study how current insecure CEC protocol practices and carelessly implemented HDMI distributions may grant an adversary a novel attack surface for HDMI devices, otherwise thought to be unreachable through traditional network means. We first present
HDMI-Walk
, a novel attack vector, that can be used by an attacker to gain arbitrary control of HDMI devices and perform malicious analysis of devices, eavesdropping, Denial-of-Service attacks, targeted device attacks, and even facilitate other well-known existing attacks through HDMI. To defend against these new HDMI-based threats on a smart network system, we further propose HDMI-Watch, a novel intrusion detection system to detect unexpected CEC-based activity within an HDMI distribution.
HDMI-Watch
operates as a standalone smart intrusion detection framework within an HDMI distribution, passively monitoring and thus imposing no additional overhead to CEC communication. To test
HDMI-Watch
's performance, we evaluated our system in a realistic HDMI testbed with a variety of consumer HDMI-enabled devices. Our extensive evaluation results show that the proposed system achieves an average 98% accuracy in classifying unexpected CEC behavior and identifies attacks occurring without any form of modification required to existing devices in an HDMI distribution.