A popular site that has a lot of users can be utilized by bad people for performing their criminal acts. Social media sites like Twitter, still can't prevent it's users totally and become the victim of virus spread and malware.
Graham Cluley from Sophos explained that there are an increasing number of viruses and malware by using URL shortening services such as goo.gl and bit.ly , and spreading via Twitter.
Users are being teased to open a link from a short message in Twitter and being directed to a fake antivirus website. The fake anti virus actually is the virus it self.
After you went to the site, it will tell and frightening you that you already have a big dangerous virus in your computer and offering you to install their anti virus. You need to pay a certain amount of money to install that fake antivirus (oops, it actually implies that you need to pay money to install the virus in your own computer).
The real danger is still continues. The fake antivirus that has been installed into someone's computer also steal username and password to their Twitter account and started to posting malicious links. Thousands of Twitter users found that their account are used to post malicious links that lead to viruses and other malicious programs without their concern.
Attacks of malicious programs that use the URL shortening service is not something new. Several of these URL shortening services are also often used by almost all Twitter users. Goo.gl and bit.ly both are the most widely used.
Therefore, the perpetrators of cyber crimes use Twitter and URL shortening services to spread their malicious programs and viruses quickly. Moreover, by utilize Twitter features, they will get a lot of victims at a time with just one post.