Viruses get attached to emails as jokes, incredible offers of prizes won, and a host of other techniques to entice the average user to open the email and allow its virus payload to go to work. Once a system is infected with this hidden accomplice, the entire contents of the machine, and the network it is attached to are potentially visible to the hacker.

Well knows applications from the largest software vendors are known to have software vulnerabilities that hackers exploit. A vulnerability is usually an unanticipated quirk of the software that has been discovered to offer unintended capabilities. Some applications literally have dozens of well-documented exploits available on the Internet for any high school student to read about and attempt on your network.

The people that discover vulnerabilities often create a procedure to allow others to reproduce their discovery. That procedure is known as an exploit in hacker parlance. The intent is to see if a weakness is always available on every computer that runs the applications, or if the problem exists only under some circumstances. This is the equivalent of laboratory testing to see what the properties are for the thing being tested. Exploits are written to allow others to test systems in a lab setting, not as a road map for a societal deviant to wreak havoc on innocent victims. Human nature guarantees that anything that's ever invented will be misused sooner or later.

This method of testing and reporting software problems to the Internet community directly evolved due to the software manufacturers repeated failures to address their problems when they were reported only to them in prior years. If a SUV were discovered to have a roll over problem that the manufacturer ignored, everyone would want to be informed of the potential to allow them to avoid the problem. The reporting of software vulnerabilities to the general public when the software manufacturer has a history of ignoring problems is the same thing. The fact that irresponsible individuals use that information in a destructive way is unintended and any harm done should be viewed ultimately as the software manufacturers responsibility for creating the problem in the first place.