Collapsed crypto exchange FTX is being advised by cybersecurity company Sygnia after FTX apparently underwent a massive hack in November, its new chief executive John J. Ray III told a Delaware bankruptcy court on Monday.

The company saw mysterious outflows worth hundreds of millions of dollars in early November, around the time it filed for bankruptcy and founder Sam Bankman-Fried resigned as chief executive officer.

Ray said he had hired technical experts in an attempt to shore up FTX’s insecure environment, and that Signia had prevented what could have been further hacking back in November.