October 28, 2010, 3:38 PM — A new variant of the Koobface worm that targets Mac OS X and Linux as well as Windows is spreading through Facebook, MySpace and Twitter, security researchers warned today.
Antivirus firms first reported the malware, dubbed "Boonana," on Wednesday when Intego and SecureMac, two Mac-only security vendors, warned Mac OS X users that the worm was aimed at them.
Boonana spreads via messages posted to social networking or microblogging sites. Those messages bait the trap with the subject "Is this you in the video?" and a link to a malicious site. People who bite and click the link are then prompted to run a Java applet.
That applet is key to the malware's cross-platform capabilities, said Symantec in a note posted to its research blog .
"The [malware] is written in Java, which is a platform independent language," said Symantec researcher Jeet Morparia. "Individual modules contain Java compiled files, which are packaged in a Java runtime executable. As long as a computer has the Java Runtime Environment (JRE) installed on it, which is often the case across all the platforms, the threat can execute itself."
Intego and Symantec noted that the worm includes several components, including an IRC connector used by the hacker to issue commands to hijacked computers, a keylogger to steal usernames and passwords, and a rootkit to hide it from security software.
Functionally, Boonana works the same as the better-known Koobface Windows worm. Koobface has been actively infecting Windows PCs for more than two years, although virulent forms used in large-scale attacks didn't appear until early 2009.
Koobface, an anagram of Facebook , is best-known for infecting PCs through spammed messages on the giant social networking service.
According to Symantec, Boonana includes a component that reads browser cookies of users logged into Facebook, then posts additional bogus messages and links on the site using those Facebook accounts.