Police in Slovenia have arrested a 23-year-old man in Maribor believed to be responsible for creating the Mariposa botnet, a collection of hacked PCs that spanned an estimated 12 million computers across the globe, according to reports.
The Associated Press cites FBI officials in Washington, D.C. stating that authorities had arrested “Iserdo,” the nickname used by the hacker alleged to have created Mariposa, a botnet that first surfaced in December 2008 and grew to infect more than half of the Fortune 1,000 companies, as well as at least 40 major banks.
Earlier this year, police in Spain arrested three of Iserdo’s associates, who allegedly used the Mariposa botnet to steal credit card accounts and online banking credentials.
The AP story doesn’t identify Iserdo, saying officials declined to release his name and the exact charges filed against him, but says that the arrest took place about 10 days ago, and that the man has been released on bond.
According to information obtained by KrebsOnSecurity.com, Iserdo’s real name is Dejan Janžekovic. Local Slovenian press reports at the time of his arrest said Iserdo was a former student at the Maribor Faculty of Computer and Information Science, but that information could not be independently confirmed.
Individuals close to the case say Janžekovic charged a few hundred dollars for each copy of the bot kit, and that sales frequently were handled by a former classmate who accepted Western Union transfers on his behalf. According to two sources, one of those who helped with the transactions was a 24-year-old woman named Nuša Čoh, pictured here in her high school photo.
Neither Janžekovic nor Čoh could be immediately reached for comment.
Update, July 29, 4:45 p.m: Janzekovic appears only to have been a person of interest in this investigation, according to a law enforcement official I spoke with today. Also, I heard back from Janzekovic himself, who acknowledged having been investigated by the FBI and Slovenian police in connection with Mariposa, and taken in to the police station for questioning. But he said he is not Iserdo, and that the authorities somehow had him mixed up with someone else. From his e-mail to me:
“I am 23 years old (the picture you found is very outdated). I am single, I work as a senior systems administrator for a telco in Slovenia. Fact is that I love technology, I love life (even though the past two weeks it was hell on earth for me), but most of all – I am innocent. Yes, you read right, innocent. I am smarter than this and such things do interest me only from the technological point, as in how to protect against them.
Oh, not to forget, my net nick was and will never be Iserdo.
It is true, that I had the FBI and Slovenian police investigating me but it is also true, that I had nothing to hide. During the investigation I was very cooperative with authorities – I even gave them password for my encrypted partitions. What was the lead to me? It had to be some kind of mix-up and/or identity theft – the only person known to me in this whole story is the girl who I went to school with (as you have already found out).
Neither of authorities did explain to me how they came to conclusion that I was iserdo. I strongly believe the case was identity theft (obviously someone who knew enough about me, to know that I would easily fit in the case) and/or connection through Nusa. And believe me, it was also to my great surprise, when they woke me up at 6 a.m. to search my home on basis of me selling some ‘nasty code’.
But know this – I do not know any technical details about the botnet, program or anything about the criminal backgrounds as I have never seen it or worked with it.”
Authorities in Spain and Slovenia were aided in their sleuthing by the “Mariposa Working Group,” a collection of security companies and experts that infiltrated the botnet late last year and ultimately wrested control of it away from criminals who had purchased access to the network.
Christopher Davis, chief executive of working group member Defence Intelligence, said his team tracked just under 700 Web site domains being used to control portions of the Mariposa botnet, suggesting that Iserdo sold hundreds of copies of the bot kit, at hundreds of dollars per kit.
Davis said Iserdo’s creation used an advanced, custom-made communications protocol designed to slip in and out of firewalls unnoticed, and that communication between systems infected with the butterfly bot and its corresponding control Web site was obfuscated by using a homegrown encryption technology.
“It’s a complicated kit he built,” Davis said. “We’re pretty good at breaking crypto, and it took us at least three days to break the cryptography around this bot, when it normally takes us an hour or so.”
Davis praised the arrests, saying it was unusual because normally it is the individuals who are using and buying the bots that are apprehended, not the bot authors themselves. Still, he said, he hopes authorities can use the information to round up the various Mariposa botnet operators.
“We need to go after all of them – the people who write the code, the people who sell it, the people who distribute it, even the money mules they use to convert stolen credit cards and banking credentials into cash,” Davis said.