Microsoft has released its ninth according to Microsoft. "Rimecud is a 'kit' family: different people working independently use a malware creation kit to create their own Rimecud botnets. Rimecud is the primary malware family behind the so-called Mariposa botnet, which infected millions of computers around the world in 2009 and 2010," the report said. "Rimecud is a backdoor worm that spreads via fixed and removable drives, and by sending malicious hyperlinks to a victim's contacts via several popular instant messaging programs. Rimecud can be commanded to take a number of typical botnet actions, including spreading itself via removable drives, downloading and executing additional malware, and stealing passwords." A 23-year-old Slovenian citizen was arrested in July for being suspected of writing the malware.