1) Inside Jobs – Gathering information about an agency from the actually agency itself through infiltration and spying.

2) Back Doors - Hackers gain access to an open or closed network by exploiting back doors administrative shortcuts, configuration errors, easily deciphered passwords, and unsecured dial-ups. With the aid of computerized searchers (bots), hackers can probably find any weakness in your network.

3) Rogue Access Points - Rogue access points (APs) are unsecured wireless access points that outsiders can easily breech. (Local hackers often advertise rogue APs to each other.) Rogue APs are most often connected by well-meaning but ignorant employees.

4) Trojan Horses - Trojan horses, these are attach their selves to other programs and are the leading cause of all break-ins. When a user downloads and activates a Trojan horse, the hacked software (SW) kicks off a virus, password gobbler, or remote-control SW that gives the hacker control of the PC.

5) Viruses and Worms - Viruses and worms are self-replicating programs or code fragments that attach themselves to other programs (viruses) or machines (worms). Both viruses and worms attempt to shut down networks by flooding them with massive amounts of bogus traffic, usually through e-mail. This is very common and hackers make new viruses and worms every day.

6) Denial of Service - DoS attacks give hackers a way to bring down a network without gaining internal access. DoS attacks work by flooding the access routers with bogus traffic (which can be e-mail or Transmission Control Protocol, TCP, packets).

Distributed DoSs (DDoS5) are coordinated DoS attacks from multiple sources. A DDoS is more difficult to block because it uses multiple, changing, source IP addresses.

7) Anarchists, Crackers, and Kiddies - Anarchists are the type of people who just like to break into stuff. They usually exploit any target of opportunity.

Crackers are hobbyists or professionals who break passwords and develop Trojan horses or other SW (called warez). They either use the SW themselves (for bragging rights) or sell it for profit.

Script kiddies are hacker wannabes. They have no real hacker skills, so they buy or download warez, which they launch.

Other attackers include disgruntled employees, terrorists, political operatives, or anyone else who feels slighted, exploited, ripped off, or unloved.

8) Sniffing and Spoofing - Sniffing refers to the act of intercepting TCP packets. This interception can happen through simple eavesdropping or something more sinister.

Spoofing is the act of sending an illegitimate packet with an expected acknowledgment (ACK), which a hacker can guess, predict, or obtain by snooping.