The world’s most powerful A-list legal firm hit by a cyberattack is refusing to pay the shadowy hackers their $42 million ransom demand — meaning that a trove of details of some of the biggest deals in showbiz history, including Bruce Springsteen’s Netflix deal and Sean “Diddy” Combs’ rumored $100 million vodka deal will be laid bare on the internet.

The US Secret Service and the FBI are continuing to probe hacking group REvil, who attacked the server of attorney Allen Grubman’s NYC firm and stole 756 gigabytes of confidential documents relating to his firm’s clients including Lady Gaga, Madonna, Mariah Carey, Priyanka Chopra and Bette Midler.

On Thursday the hackers upped the ante by doubling their ransom demands and threatening to publish “a ton of dirty laundry” on President Donald Trump — who is not a client of the NYC law firm Grubman, Shire, Meiselas and Sacks — next week if the law firm did not pay in full. It remains unclear if the hackers claims to have dirt on Trump are true.

A source with knowledge of the hack told Page Six, “Grubman isn’t going to pay these cyber-terrorists a penny, so it is likely all his files will end up released by the hackers. The interesting details in there could include U2’s lucrative publishing deals with Universal, worth an estimated $300 million, as well as Springsteen’s deal with Netflix, estimated to be worth $20 million, as well as how much Diddy actually made in that Ciroc vodka deal.”

The source added, “Often, the most damaging details are in the personal emails of the stars and the executives — which is what happened with the 2014 Sony hack. But it is not known how many personal emails have been stolen from the Grubman hackers.” The hackers have not specifically threatened to reveal details on these stars nor these specific deals.

On Thursday REvil posted a host of documents relating to Lady Gaga on their dark web site, but most appeared to be standard industry contracts.