Hardware Allows Activation of Test or Debug Logic at Runtime

Attackers exploit this weakness by accessing hardware test modes—like debug interfaces or error injection circuits—that were intended only for development or manufacturing. Once activated, these features can grant unauthorized read/write access to system memory, registers, or buses, allowing an adversary to directly modify the device's behavior or extract secrets. For example, an accessible debug mode might let an attacker intercept or alter data on a communication bus, leading to malicious message injection. Similarly, runtime error injection could corrupt cryptographic operations or expose keys. These capabilities effectively create backdoors that compromise both system integrity and data confidentiality.