The FBI secretly withheld the key that would have decrypted data and computers on up to 1,500 networks last summer, when the notorious Russian ransomware group REvil launched a series of high-profile attacks on prominent organizations and companies.
The FBI was able to break into the REvil gang’s servers to get the key, but after talking to other agencies, the bureau decided to wait before sending it to the victims for fear of tipping off the criminals.
REvil closed on July 13 before the FBI could intervene, but for reasons still unknown, the FBI did not release the key until July 21.
“We make the decisions as a group, not unilaterally,” FBI Director Christopher Wray told Congress on Tuesday. “These are complex decisions designed to create maximum impact, and that takes time in going against adversaries where we have to marshal resources not just around the country but all over the world.”
REvil has a long history of employing high-pressure tactics to extort victims. The Russia-based gang first materialized in 2019 and went on a rampage earlier this year.
Last week, cybersecurity firm Bitdefender released a universal decryptor tool for networks and computers that were encrypted before REvil shut down on July 13. About 250 victims have used the tool so far.
Despite the FBI’s efforts to stop the group, REvil returned from hibernation this month with a new series of attacks that affected at least eight new victims. Bitdefender no longer worked for the new victims, a sign that REvil has retooled its operations after brief downtime.
For more information, read the original story in Ars Technica.