The Security Mentor

Some of those annoying animated ads, a few online games, and a very few legitimate uses involve a program called Shockwave that helps out your browser by interpreting what are called Flash files downloaded from the web. If you're missing the Shockwave player, you see a little box urging you to install a "plugin" instead of seeing an obnoxious ad.

The Shockwave player has a disgusting history of security bugs that could let bad guys compromise your computer by putting toxic Flash files on a web site you visit. It just had two more.

Security writer Brian Krebs has a good article about the latest Shockwave bugs. His article explains how to tell what version you have and where to download the fix.

Or you could just uninstall the [censored] thing altogether. If you keep it, you can save a lot of annoyance and security risk by installing the Flashblock extension to Firefox. I don't know if there's anything comparable for Opera. Flashblock prevents automatic loading and playing of the Flash files. If you really want to see one, you can click on the blank box where it would normally go, and it will start.