The ransomware group LockBit has claimed responsibility for the January Royal Mail cyberattack and today is making threats to Britain’s centuries-old service.

After the attack happened on Jan. 12, the Royal Mail said it had to close down international shipping because of “severe service disruption.” At the time, it was speculated that LockBit, which may have connections to Russia, was behind the attack, but cogent evidence was lacking. Lockbit also then denied it was behind the attack.

There doesn’t seem to be any question now that LockBit was behind the attack after the gang published messages stating that if a ransom is not paid, it will release a significant amount of stolen data from the Royal Mail Feb. 9 on the dark web, the shady corner of the internet reachable with special software.

It’s hardly an ideal time for the service, given it’s in the middle of strike actions over pay and conditions that have already cost millions of pounds. That might not concern the hackers, who have been busy of late disrupting a financial services company in the U.K. and, before that, holding a children’s hospital to ransom – for which the group later issued an apology.

“Royal Mail is aware that an unauthorized third party has said it plans to publish some data allegedly obtained from our network,” the service said in a statement to the media. “The cyber incident impacted a system concerned with shipping mail overseas. At this stage of the investigation, we believe that the vast majority of this data is made up of technical program files and administrative business data.”

Although the Royal Mail said the data does not contain any “financial information” or other types of data that might be deemed sensitive, a hack of the country’s critical national infrastructure is far from benign. Right now, the service is still struggling from the fallout of the attack, announcing on its website that it’s making progress, but disruptions in international mail are ongoing.

“Our teams are continuing to work around the clock to reinstate remaining export services as quickly as we can,” wrote the service, although considering it ships to 200 nations and territories and every day last year sent about 200,000 parcels, any significant delays can be considered severe.

Photo: Tom Page/Flickr