This type of attack has become much more prevelant with the advent of businesses being on the internet, because there is a lot to be gained, the attacks don't take as much work as social engineering and physical access, and there are many, many problems with the internet protocol, network stacks on various operating systems, network servers and services, and bad administrators. The Strategies There are many strategies for attacking. Usually these strategies are used in combination to make a complete attack. Abusing trust Trust relationships make a cracker's job easier. Trust is security's antitheses, so never trust anything if possible.
Most security breaches stem from too much trust.
Eavesdropping Eavesdropping is often times a good attack strategy. If the cracker just wants to gather information, without being detected, eavesdropping serves that need. Replay Replay is when a cracker uses an old session that they eavesdropped on again. This way you can set up miscommunication between two or more trusting parties. Passive Cheating Passive cheating is when an attacker uses a standard protocol, but bends the rules in able to do something malicious to the system under attack.