Top celeb attorney Allen Gruban's website has been attacked, and the hackers have threatened to reveal personal details of A-listers like Lady Gaga and Elton John if they are not paid $21 million.

The New York-based attorney's website "Grubman Shire Meiselas & Sacks" is down, and the hackers have claimed to be in possession of 756 gigabytes of data including contracts and personal e-mails. As a warning, a screenshot purported as a contract for Madonna has already been released. They have also uploaded an image in which they claim to be showing the stolen data directory with folders named under certain clients.

According to a report in Page Six, multiple sources have confirmed that the Federal Bureau of Investigation is working on the case, while the law firm has notified its famous clients about the threat.

A source told the outlet that the hackers managed to get into the system while everyone was focused on the coronavirus. There are speculations that the hackers are Eastern European, though there is no confirmation yet. They are reportedly known as REvil or Sodinokibi, and were in news in January for attacking foreign exchange company Travelex with a malware that encrypts data until a ransom is paid in untraceable cryptocurrency bitcoin.

"They are demanding a $21 million ransom, and the firm is not negotiating with them," the source said, adding that the law firm has "sensitive details on everything — work contracts, confidential settlements and endorsement deals for the biggest stars in New York and Hollywood."

Meanwhile, the law firm released a statement to address the issue and stated: "We can confirm that we've been victimized by a cyberattack. We have notified our clients and our staff. We have hired the world's experts who specialize in this area, and we are working around the clock to address these matters."

Other A-listed musicians represented by the firm include Lizzo, Barry Manilow, Rod Stewart, Lil Nas X, The Weeknd, U2, and Drake. Priyanka Chopra, Robert De Niro, Sofía Vergara, LeBron James, and Mike Tyson are also clients of Grubman's firm.

Lady Gaga and Elton John
Lady Gaga and Elton John Reuters

A spokesperson for the firm noted that HBO, Zoom and the Texas court system have also been victims of similar attacks, and said that their high-profile clients have "expressed overwhelming support" to the organisation as they understand it is the latest victim of this "global extortion scheme."