Now that we have put the unintentional threat into context, let's look at how an actual exploit can take place. Let's also look at how a NAC solution could prevent this from happening. Since everyone I talk to mentions that their biggest concern with letting outsiders onto their LAN is infection, let's use that example.
There are two main ways in which unintentional malware infection can take place on a LAN:
When talking about malware, many people generically call everything viruses. In reality, there are many different types of malware, such as viruses, worms, Trojans, spyware, and so on. While technically calling all of these things viruses is wrong, it's a fairly common thing to do. Purists may try to correct you from time to time, but it really doesn't matter. That notwithstanding, it is important to realize the difference between the different pieces of malware. Here are three really quick definitions on some of the major pieces of malware that will be important to understand for the purposes of this real-world example:
Viruses — Malware that spreads by human interaction, such as opening a file
Worms — Malware that spreads without human interaction
Trojans — Malware that is installed covertly during the execution of a host file
Malware can also be a mix of different types of malware. For example, a piece of malicious code could be transferred from one machine to another by sharing files via a USB drive. ...