Network Access Control For Dummies®

2.2. That's Why They're Called Trojan Horses

Today, users are accessing networks from anywhere in the world, at any time of day, through an array of access technologies and devices that may run any number of operating systems and applications. Although mobility has helped raise productivity and profits for companies around the world, it has also meant sleepless nights and headaches for administrators and trouble for their networks. Administrators now have no idea where a user's device — whether it's managed by the company or not — has been before it attempts to access the enterprise network. The user could have been surfing the Internet and accessed Web sites that carried hidden dangers (such as worms, keystroke loggers, rootkits, botnets, backdoors, or other nefarious forms of malware). Or, even though company policy may forbid it, the user may have allowed his or her child, significant other, or another individual to use his or her device; that person may have launched a chat site or sent an instant message to friends, or even disabled antivirus or other anti-malware checks because they made the PC run too slow, providing an open invitation to malware or other culprits.

These and other traps could be lying in wait for the user whom the company trusts and who uses a trusted, managed device. When that user reconnects to the company's network, the malware or hack lying in wait uncoils its wrath upon an unknowing company network, that network's users, and its connected devices. ...