Penetration testing: 'One false click' can let hackers in
7 June 2013 Last updated at 00:16 BST
Many users of the internet think that by not replying to 'phishing scams' - false invitations encouraging you to hand over personal information - they are safe online.
But hackers use increasingly sophisticated techniques to trick more savvy web users and gain control of their computers.
Trustwave Spider Labs of London is a professional penetration tester, hired by companies to test vulnerabilities in their cyber security.
Michele Orru, a senior security consultant at the firm, demonstrated to LJ Rich how by simply clicking on a single malicious link, you can fall prey to the control of a hacker, because of security issues connected with common browsers.
This is the second video in a series about penetration testers - in the first, LJ Rich learned how hackers can get control of webcams.
Video Journalist: Dougal Shaw