Numerous documents from the company have been leaked online. These include business contracts, accounts statements, confidential memos, and other general documents.
HLB, which gets its names from its founders, has 21,000 staff and 60 offices worldwide.
The company had about US$3 billion in revenue in 2019. The group's global site appears to be down, indicating that it may have been the avenue for the Maze attack.
But whether these attacks are paying off is doubtful; it is only when victims refuse to pay up that the people behind Maze post data from these victims online.
If an attack ends in the victim paying, the name of the victim is not published.
iTWire has contacted HLB for comment.