Modern vehicular systems are comprised of numerous electronics control units (ECUs) that consist of thousands of microelectronics components. Individual ECU systems are reliant upon “trust” in the supply chain for defense. This paper describes an approach utilizing historically offensive-based cybersecurity technology, side-channels, to quantify and qualify malicious ECU states in a bus- agnostic, logically-decoupled method of assurance and verification. Providing a measure of supply chain assurance to end-users.