A unit of Japan's Toshiba Corp said on Friday it had been hacked in Europe by the DarkSide ransomware group widely believed to have been behind a crippling fuel pipeline attack in the United States this week.

WHO ARE DARKSIDE?

Experts who have tracked DarkSide said it emerged in the middle of last year and appears to be composed of veteran cybercriminals who are focused on squeezing as much money as they can from targets. "They're very new but they're very organized," Lior Div, thechief executive of Boston-based security firm Cybereason, saidthis week when asked about the Colonial Pipeline attack. "It looks like someone who's been there, done that."

It seems to spare Russian, Kazakh and Ukrainian-speakingcompanies, suggesting a link to the former Soviet republics.

HOW DOES IT WORK? DarkSide is one of a number of increasingly professionalizedgroups of digital extortionists, with a mailing list, a presscenter, a victim hotline and even a supposed code of conductintended to spin the group as reliable, if ruthless, businesspartners.

DarkSide uses the method of double extortion, which involves demanding separate sums for both a digital key needed to unlock any files and servers, and a separate ransom in exchange for a promise to destroy any data stolen from the victim, according to the specialist blog KrebsonSecurity https://krebsonsecurity.com.

Bloomberg reported that Colonial Pipeline paid nearly $5 million in ransom.

The Krebs blog also said DarkSide offers to tip off investors about its victims in advance to allow them to short stocks and benefit from the price fall when the hack becomes public.

OTHER VICTIMS?

After being blamed for the Colonial Pipeline attack, DarkSide this week claimed responsibility for breaking into three more companies, saying it was publishing hundreds of gigabytes of data from a Brazilian battery firm, a Chicago-based tech company, and a British engineering firm.

Reuters was not immediately able to verify the claims.

Experts said DarkSide has unleashed a digital crimewave.

"It's as if someone turned on the switch," said Div, whonoted that more than 10 of his company's customers have foughtoff break-in attempts from the group in the past few months.

HALL OF SHAME

DarkSide's site on the dark web features a Hall of Shame-style gallery of leaked data from victims who haven't paid up, advertising stolen documents from more than 80 companies across the United States and Europe.

In some ways DarkSide is hard to distinguish from theincreasingly crowded field of internet extortionists.

It also has a public relations program, as others do,inviting journalists to check out its haul of leaked data andclaiming to make anonymous donations to charity.

TECH ISSUES

Its tech savvy is nothing special, according to Georgia Tech computer science student Chuong Dong, who published an analysis.

According to Dong, DarkSide's code was "pretty standardransomware." Div said that what does set them apart is the intelligencework they carry out against their targets beforehand. Typically "they know who is the manager, they know whothey're speaking with, they know where the money is, they knowwho is the decision maker," said Div.

  - Reuters