Imagine trying to fend off burglars in a house with all the doors and windows left open. Sure, you can manage for a while with a Doberman and a shotgun, but being able to lock up might just help you sleep better.

That's more or less the situation in which computer users find themselves. According to Secunia, the typical Internet user has a dozen insecure applications on his or her computer.

Data gathered by the company indicates that PC users have, on average, 80 applications installed and that 15% of them are not up to date.

The main reason that software makers release update patches is to fix known vulnerabilities.

"Unpatched programs can lead to silent installations of malicious code simply by visiting a Web site, opening a PDF, a movie, or other 'innocently' looking file types and content," said Secunia IT development manager Jakob Balle in a blog post. "If you want to feel safe from drive-by-attacks and when opening e-mail attachments, then you need to get patching now."

Only 2% of PC users have all their applications up-to-date, according to the company.

Secunia argues that keeping programs up-to-date is more important than running antivirus software or using a firewall. Antivirus software makers and firewall vendors have a slightly different perspective.

Even so, reports from other organizations underscore the value of rapid patching. A study released in May by Thomas Duebendorfer of Google Switzerland and Stefan Frei of the Swiss Federal Institute of Technology (ETH Zurich) found that Chrome's automatic, silent update mechanism offered greater security than the update methods used by competing browsers.

Secunia offers free software called Secunia PSI (Personal Software Inspector) to help PC users identify programs that need to be fixed.

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