Security: Where Testing Fails

Computer security addresses the problem of enforcement of security policies in the presence of malicious users and software. Systems enforcing mandatory policies can create confinement domains that limit the damage incurred by malicious software executing in applications. To achieve assurance that the confinement domains cannot be breached, the underlying enforcement mechanism must be constructed to ensure that it is resistant to penetration by malicious software and is free of malicious artifacts. The limitations and contributions of testing in achieving these goals are discussed.