Hijack...

Tyler aimed to infiltrate Zack's network, so he could set up a secret eavesdropping post and capture credit card numbers, passwords and other sensitive data flowing between computers on that network and sites their browsers have deemed safe.

In an even more nefarious plot, Tyler could hijack the auto-update feature on a victim's computer, and trick it into automatically installing malware pulled in from a hacker's Web site. The computer would think it's an update coming from the software manufacturer.