The Russian man accused by Microsoft of creating and operating the Kelihos spam botnet said on Friday he's innocent.
Microsoft said that Andrey Sabelnikov, a programmer who lives in St. Petersburg, Russian Federation, "created, operated and controlled the Kelihos botnet," which at its peak comprised an estimated 45,000 compromised Windows PCs. Those systems were used to transmit up to 4 billion spam emails daily, Microsoft has alleged.
In an emailed statement today, Microsoft declined to comment on Sabelnikov's claim of innocence. "As this is a case pending in court, we cannot comment further except to say that we look forward to seeing Mr. Sabelnikov in court so we can continue this discussion," said Richard Boscovich, a senior attorney with Microsoft's Digital Crimes Unit.
Last week, Microsoft added Sabelnikov to the list of defendants in a lawsuit first filed in September 2011, when it used a court order to take down Kelihos by commandeering its command-and-control (C&C) servers. Microsoft said its analysis showed evidence in the malware code of Sabelnikov's participation.
Sabelnikov begged to differ.
"I did not commit this crime, have never participated in the management of botnets and any other similar programs, and especially [have] not extracted from it any benefit," he wrote in a Friday blog (in Russian, with Google Translate version here)
Over the weekend, Sabelnikov contacted the BBC, which first reported his claims of innocence.
In his blog, Sabelnikov also said he had returned to Russia from the United States, where he had been on business, when he learned of the charges leveled by Microsoft.
Russian law bans extradition of its citizens to face trial in other countries.
Sabelnikov worked for a pair of security firms, Agnitum and Returnil, from 2005 through late 2011, resigning from the latter on Dec. 21, 2011, according to that company.
Returnil said it was "extremely disappointed and angered that someone who was a member of our team could be implicated in this type of activity."
Other security researchers have said that it was possible that Sabelnikov obtained the source code to another bot Trojan -- dubbed "Waledac" -- during his work at his former employers, or through his own probing of hacker forums. Kelihos, some experts believe, shares characteristics with Waledac.
"I want to emphasize that I do not have any relation to the activities [of] Kelihos and spam," Sabelnikov said. "Unfortunately, an avalanche of press coverage, indicating false facts [and] distort[ing] reality, [have] unwittingly caused the companies where I [have] worked and [now] work ... a huge moral hazard and [an] impact on [their] business reputation."
Sabelnikov has not replied to requests for comment sent to his Skype account.
Sabelnikov has until the middle of February to answer Microsoft's charges, or face a default judgment, according to court documents.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His e-mail address is firstname.lastname@example.org.