One of the central figures believed to have been behind the Mariposa botnet is on trial in Slovenia.
The suspected mastermind of the botnet, Matjaž Škorjanc, 26, is believed by the authorities to be the hacker known as "Iserdo." Authorities arrested him in Slovenia arrested in 2010. At its height, Mariposa was composed of more than 8 million zombie computers infected with the Butterfly bot (Mariposa is Spanish for butterfly).
In a blog post, Sophos Security Consultant Graham Cluley noted that the hijacked computers were infected with the polymorphic W32/Rimecud family of malware, which spread through a number of means, including copying itself to removable storage devices, instant messaging and P2P file-sharing.
"Once a computer had been compromised and brought into the botnet, operators could steal information from innocent users - including credit card details and banking passwords," he blogged.
In 2009, an international team researchers and experts formed the Mariposa Working Group (MWG) to take the botnet down. In February of 2010, the Spanish national police arrested three people suspected of being tied to the botnet.
At the time of his arrest, the FBI said Iserdo sold the butterfly bot to cyber-criminals worldwide from 2008 to 2010. These individuals in turn developed networks of infected bots, of which Mariposa was the largest and most notorious. In addition to selling Butterfly Bot, Iserdo also created customized versions for certain customers and sold plug-ins to bolster the botnet's features and functionality.
"In the last two years, the software used to create the Mariposa botnet was sold to hundreds of other criminals, making it one of the most notorious in the world," FBI Director Robert S. Mueller, III, said in a statement at the time. "These cyber intrusions, thefts, and frauds undermine the integrity of the Internet and the businesses that rely on it; they also threaten the privacy and pocketbooks of all who use the Internet."