"Once cookies related to the monitored social-networking Web sites are located, it connects to these Web sites using the user log-in session stored in the cookies. It then navigates through pages to search for the user's friends. If a friend has been located, it sends an HTTP POST request to the server," Trend Micro reports.

Ultimately, the worm's agenda is to transform the victim's computer into a zombie and form botnets for malicious purposes. Koobface attempts to do this by composing a message and sending it to the user's friends. The message contains a link to a Web site where a copy of the worm can be downloaded by unsuspecting friends. And the cycle repeats itself.

Once Koobface finds the social-networking cookies, it makes a DNS query to check IP addresses that correspond to remote domains. Trend Micro explains that those servers can send and receive information about the affected machine. Once connected, the malicious user can remotely perform commands on the victim's machine.