8.3 Program and System Threats

A threat is a possible danger that might exploit a vulnerability to breach security and thus cause possible harm

Program threats
When a program written by one user may be used by another user, misuse and unexpected behavior may ensue. Some methods by which this behavior may occur are: Trojan horse, trap door, and stack overflow.

System threats
Perhaps the most sophisticated types of threats to computer systems are presented by programs that exploit vulnerabilities in computing systems. In such an environment, it is possible to create a situation where operating system resources and user files are misused. Some methods by which this behavior may occur are: worms and viruses.