The computer hackers and phishing experts 'on our side'
21 June 2013 Last updated at 15:58 BST
If you have been hacked it means someone somewhere is watching your computer's every move. Hackers deploy a variety of tricks to gain access to your computer but a fight-back has begun. Some companies are now even paying hackers to test their own firm's security.
LJ Rich meets some professional hackers who are on the right side of the law, explains how people go about trying to get inside your computer and has some useful tips on how to stay safe from unwanted invaders.