A test of a network's vulnerabilities by having an authorized individual actually attempt to break into the network. The "pen tester" may undertake several methods, workarounds and hacks to gain entry, often initially getting through to one seemingly harmless section, and from there, attacking more sensitive areas of the network.
Security experts recommend that an annual penetration test be undertaken as a supplement to a more frequent automated security scan. See
security scan and
ethical hacker.