A rather nasty bug has been found in Flash which allows a malicious website to run arbitrary code– for all intents and purposes what this means is the site owner can take complete control over your computer. I won’t explain botnets here, but typically computer taken over in this fashion function normally to the person using them but are also twisted to send out massive amounts of spam to both email hosts and to comment forms on sites like this one, host web sites used in online fraud (phishing), run hacking operations, and run extortion rings based on distributed attacks which can take down pretty much any website. This is done without the computer owner’s consent or knowledge. Pretty much every piece of spam you get is from one of these compromised systems. And we all hate spam, don’t we?
If you’re a responsible computer owner, you should make sure your browser and operating system are patched up, but usually the Flash player is neglected in these upgrades. (Flash is used to display videos on YouTube, ad content on websites, and interactive stuff like online games.) You can check here if your Flash player is up to date, and if the version is less than what’s listed on the chart you should download and install the latest version immediately.