The security firm says Twitter users may see a tweet in their stream that reads 'my home video :)' or 'cool video! WOW'. The message includes a link that redirects users to a set of spoofed social networking pages and the pages then prompt for a plugin install, often stating 'Flash Player required' which contains the malicious threat with the link 'setup.exe'.
Once it has successfully infected a PC, Koobface attempts to gather credit card details and other sensitive information.PC Tools is warning Twitter users to be wary when receive messages from someone they don't know.
"This is another example of how cybercriminals are trying to capitalise on sites such as Twitter with large public interest,"said Michael Greene, vice president of product strategy at PC Tools.
As with any threat, it's important that consumers know what to look out for and treat suspicious links with caution.
This is not the first time Koobface has targeted Twitter users. Last month, Twitter was forced to suspend the accounts of Twitter users infected by the worm. Other sites targeted by Koobface include Bebo, Hi5, Friendster and LiveJournal.
This story, "Twitter Targeted by Familiar Worm" was originally published by PC Advisor (UK).