CWE-1259: Improper Restriction of Security Token Assignment

Extended Description

Systems-On-A-Chip (Integrated circuits and hardware engines) implement Security Tokens to differentiate and identify which actions originated from which agent. These actions may be one of the directives: 'read', 'write', 'program', 'reset', 'fetch', 'compute', etc. Security Tokens are assigned to every agent in the System that is capable of generating an action or receiving an action from another agent. Multiple Security Tokens may be assigned to an agent and may be unique based on the agent's trust level or allowed privileges. Since the Security Tokens are integral for the maintenance of security in an SoC, they need to be protected properly. A common weakness afflicting Security Tokens is improperly restricting the assignment to trusted components. Consequently, an improperly protected Security Token may be able to be programmed by a malicious agent (i.e., the Security Token is mutable) to spoof the action as if it originated from a trusted agent.