This week an insidious and evil attack has been discovered that spreads via Twitter. The messages usually come across like an innocuous inquiry from a pal, asking "It's you on photo?" or "It's about you?", followed by a URL. When a user clicks on that, a webpage opens up and distributes a particularly nasty bit of kit called Blackhole. It doesn't directly attack your computer, but goes through the system, figuring out what its vulnerabilities are. Then it puts every viable piece of malware onto it.

Horrified? You should be. Finding and removing a virus or trojan is one thing — dealing with a load of malware is a nightmare and a massive security risk. But it doesn't have to happen to you. Luckily, the best defense is common sense.

Most of us avoid suspicious emails or messages with bizarre links, yet we often click willy-nilly on Twitter links. Maybe it's because we're used to seeing odd-looking links from shorteners like Bitly or TinyURL, so we let our guard down and blindly accept any URLs we see. But that's exactly why this exploit kit has spread, so staying vigilant is key, regardless of what program or service you use.

Be wary of strange links (including any from the domains below) and use a URL expander, so you always know where you're going. Again, do not visit these domains if you care about the integrity of your system. But do bear them in mind, so you can avoid them.

Have you seen one of these messages in the Twitterverse?