An abstract of “Subversion: The Neglected Aspect of Computer Security”
This thesis distinguishes three methods of attacking internal protection mechanisms of computers: inadvertent disclosure, penetration, and subversion. Subversion is shown to be the most attractive to the serious attacker. Subversion is characterized by three phases of operations: the inserting of trap doors and Trojan horses, the exercising of them, and the retrieval of the resultant unauthorized information. Insertion occurs over the entire life cycle of the system from the system design phase to the production phase. This thesis clarifies the high risk of using computer systems, particularly so-called ‘trusted’ subsystems for the protection of sensitive information. This leads to a basis for countermeasures based on the lifetime protection of security related system components combined with the application of adequate technology as exemplified in the security kernel concept.
