Physical Attack: The computer infrastructure is damaged by using conventional methods like bombs, fire, etc.
Syntactic Attack: The computer infrastructure is damaged by modifying the logic of the system in order to introduce delay or make the system unpredictable. Computer viruses and Trojans are used in this type of attack.
Semantic Attack: This is more treacherous as it exploits the confidence of the user in the system. During the attack the information keyed in the system during entering and exiting the system is modified without the user’s knowledge in order to induce errors.
