Husch Blackwell is emphasizing that it was not directly subject to a data breach after a hacker claimed on New Years Eve that it was in possession of legal documents created by its predecessor firm pertaining to the 9/11 attacks.

As reported by the Financial Times, a hacker or group of hackers calling itself The Dark Overlord announced that it had hacked insurers Hiscox and Lloyds of London, along with World Trade Center owner Silverstein Properties. In doing so, The Dark Overlord said it had obtained a trove of documents from Blackwell Sanders Peper Martin, which is now Husch Blackwell.

The hackers made images from 16 documents available online. These involve filings from the “In re Terrorist Attacks on September 11, 2001” litigation in the Southern District of New York from Blackwell Sanders. The firm was retained by Lloyds to recover losses suffered in the 9/11 attacks and a document also reveals a 2002 invoice for Hiscox. The documents also include correspondence from other law firms involved in the matter and additional fragments connected to the litigation.

The Dark Overlord did not claim it had hacked Husch Blackwell itself, and the firm issued a statement denying that it had been hacked.

“Several documents bearing the letterhead of a predecessor law firm to Husch Blackwell were made public earlier this week by a cyber terrorist group,” the firm said in a statement. “After a thorough review Husch Blackwell can confirm that no documents were obtained from Husch Blackwell and that there was no unauthorized access to Husch Blackwell systems, client files, documents or data.”

Husch Blackwell acknowledged that the documents made public related to a representation that stemmed from the 9/11 attack on the World Trade Center, but it noted that the attorneys in charge of the matter left Blackwell Sanders in early 2002 and took the representation with them, putting an end to the firm's connection to the litigation.

“Information available to us indicates that any breach relating to the documents recently made public occurred at another firm,” the firm added.

In April 2018, Hiscox acknowledged that a “specialist law firm” in the U.S. that provided advice to Hiscox had been hacked and information connected to as many as 1,500 of Hiscox's US-based commercial insurance policyholders had been accessed.

After the Dark Overlord announced the hack Monday, the insurer issued a statement noting that posts appearing online were connected to the earlier announcement. The firm did not name the law firm that it claimed was responsible for the breach and did not answer a further inquiry.

“The law firm's systems are not connected to Hiscox's IT infrastructure and Hiscox's own systems were unaffected by this incident,” a company spokesman said. “One of the cases the law firm handled for Hiscox and other insurers related to subrogation litigation arising from the events of 9/11, and we believe that information relating to this was stolen during that breach.”

The hacker claimed that the initial 16 documents were part of 18,000 that it had in its possession, and that it intended to sell them for Bitcoin to anyone interested, including terrorist organizations like ISIS and Al-Qaeda as well as U.S. geopolitical rivals China and Russia.

It also had a message for parties involved in the litigation who would likely prefer to see their documents remain private:

“If you're one of the dozens of solicitor firms who was involved in the litigation, a politician who was involved in the case, a law enforcement agency who was involved in the investigations, a property management firm, an investment bank, a client of a client, a reference of a reference, a global insurer, or whoever else, you're welcome to contact our e-mail below and make a request to formally have your documents and materials withdrawn from any eventual public release of the materials. However, you'll be paying us,” The Dark Overlord said, in an announcement posted on Pastebin.