Twitter has had its share of security problems over the past months. Earlier this year someone gained access to the Twitter accounts of U.S. President Barack Obama, Britney Spears, and others.

Recently scammers have become more aggressive on the site. They will set up new accounts and post spam messages on hot topics in hopes of gaining clicks when people search through Twitter.

And while hacked Twitter accounts are still rare, they're a much more effective way to reach victims, according to Rik Ferguson, a researcher with Trend Micro. "If you can take over an account that has a couple of thousand follower then you can get a much better return on your investment"

The Trojan link posted by Guy Kawasaki has been followed by more than 1,600 people, according to Gary Warner, director of research in computer forensics with the University of Alabama at Birmingham.

If a Windows user actually falls for the scam and downloads the Trojan linked by Kawasaki, the software will change his DNS (domain name system) server to one that is controlled by the hackers. That gives them away to steal more information, such as Twitter passwords or even online banking credentials, Warner said. "You're going to be using a DNS server that's controlled by criminals who can point you to whatever Web site you want and you'll believe it's the site you typed into your browser."