Any computer connected to the internet is a target.

Even if a computer literally contains no data, hackers still find value in it. Every computer has raw computing power and an internet connection, which can be exploited for a number of hacking schemes. The list below is a sampling of possible uses hackers have for your computer, ordered from primitive to sophisticated:

• To send unwanted spam.
• To perpetrate click fraud (A type of Internet crime that occurs in pay-per-click online advertising when a person, automated script or computer program imitates a legitimate web user clicking on an ad, for the purpose of generating a charge per click).
• To send malicious emails to your friends, family and clients; essentially, your machine becomes a spreader of viruses, malware and spyware.
• To install a keylogger and capture every username and password typed; they can then use your very own computer to log into your financial accounts; conduct transactions and perpetrate electronic theft.
• To mount a coordinated attack on select targets, such as banks or governmental institutions.
• To sniff out other traffic on your network. Any networked computer can be used to "sniff" out and copy traffic on your network, such as the network traffic from credit card or other data processing servers.
• To use your computer to send out data via the internet. In extreme cases, they may set it up as a hub to exchange illicit, illegal or stolen materials, as a relay station (proxy) to hide the true origin of certain content and communications or as a message board for shady activities.

Once a hacker gets a foothold, they can easily expand that foothold to every other computer on your network, through a variety of techniques. For examples of how hackers get into computers and computer networks, please see "Examples of Attacks."

When your computer gets hacked

If your computer or a computer on your network gets hacked, the most important task is detection. Until detected, it is impossible to contain, isolate and clean up the hack. Three things work against easy detection:

1. The hackers do not want you to know the hack has occurred or that they are using your computer;
2. Today's computers have greater computing power;
3. Faster internet connection speeds.

In many cases, computer users may not even notice that their computer has been compromised (which is exactly what the hacker wants). To hide their tracks, hackers even go to the extent of using "antiforensics" — hacking tools that are designed to evade antivirus programs and the digital forensics programs computer investigators use to find evidence.

One common feature of hacked computers, which is easier to detect than an unobtrusive illicit program running on a computer, are the communications that the malware sends out (and receives). To detect these transmissions, packet capture is very effective, when used to capture and record all Ethernet / IP transmissions in their entirety (sporadic packet capture is insufficient in these circumstances because there is no way to tell when the network activity you are searching for will occur). The information captured by a packet capture appliance would also reveal the scope of the hack, as well as identify any data that may have been stolen. This exact knowledge aids in remediation efforts, as well as in determining the scope of possible liability (for example, if the personal or financial information of a third party, such as a customer, was stolen).