Security vendor Qualys is offering a free scanning service for the 20 most serious vulnerabilities recognized by SANS, a global nonprofit security training organization.

ZDNet UK has found that the service also lets users carry out vulnerability scans on other people's computers. Though Qualys said it has put a number of preventative measures in place to stop this, it hinted that this was possible

I'm guessing that the risk of using this is more than offset by a user plugging a few holes on their system. Raises the question again of what is worse, what you have or what you might get.