Wannacry ransomeware attack preventer accused of creating bank malware

California: A British computer security researcher hailed as a hero for thwarting the "WannaCry" ransomware onslaught was in US custody on Thursday after being indicted on charges of creating malware to attack banks.

Marcus Hutchins, known by the alias "Malwaretech," was charged in an indictment dated July 12 and unsealed by federal authorities in Wisconsin.

Hutchins was in Las Vegas, where a major Def Con hacker security conference took place over the weekend. Twitter postings from other security researchers said he was arrested as he prepared to fly back to Britain.

The indictment accuses Hutchins and another individual of making and distributing Kronos "banking Trojan," a reference to malicious software designed to steal valuable information related to online financial transactions.

The indictment set the time of the activity as being from July 2014 to July of the following year.

Hutchins was part of a conspiracy to distribute the hacking tool on so-called dark markets, according to the indictment signed last month by US Attorney Gregory Haanstad.

The FBI and US Department of Justice did not respond to an AFP request for comment.

Lawyers at the San Francisco-based online rights group Electronic Frontier Foundation said they were looking to contact Hutchins.

"The EFF is deeply concerned about the arrest of Marcus Hutchins, a security researcher known for shutting down the WannaCry ransomware. We are looking into the matter, and are reaching out to Hutchins," a statement from the group said.

A spokesperson for the British Embassy in Washington said only that they "are in touch with local authorities in Las Vegas following reports of a British man being arrested."

Hutchins was hailed as a hero in May for finding and triggering a "kill switch" for a WannaCry ransomware attack that was spreading wildly around the world, locking away data on computers and demanding money for its release.

Andrew Mabbitt, another security researcher who was with Hutchins in Las Vegas, said he did not believe the allegations against Hutchins.

"He spent his career stopping malware, not writing it," Mabbitt said on Twitter.