Penetration Testing

While vulnerability scans look for potential weaknesses, a penetration test actually tries to get past your defenses and into your system.

In other words, a vulnerability scan may tell you that you are missing a patch on one of your workstations that could be exploited remotely, while a penetration test could exploit that weakness and cause a frowny face to pop up on your screen and announce "You've been hacked!"

Penetration testing should be done periodically to ensure that your system is secure.