The Ministry of Defence is investigating claims that Russian hackers have stolen hundreds of sensitive military documents and published them on the dark web.
The files hold details of eight RAF and Royal Navy bases as well as Ministry of Defence staff names and emails, The Mail On Sunday reported.
Cybercriminals accessed the cache of files by hacking a maintenance and construction contractor called Dodd Group.
The company said a ransomware attack had gained temporary access to its internal systems.
A Ministry of Defence (MoD) spokesperson said: “We take a robust and proactive approach to cyber threats that could pose risks to national interests.
“We are actively investigating claims that information relating to the MoD has been published on the Dark Web.
“To safeguard sensitive operational information, we will not comment any further on the details.”
A Dodd Group spokesperson said: “We can confirm that the Dodd Group recently experienced a ransomware incident whereby an unauthorised third-party gained temporary access to part of our internal systems.
“We took immediate steps to contain the incident, swiftly secure our systems and engaged a specialist IT forensic firm to investigate what happened.
“While our forensic investigation is ongoing, we are aware of claims that data taken from our systems have been published online.
“We are taking these claims extremely seriously and are working hard to validate this. We are in contact with our customers and colleagues and have also notified the relevant regulatory authorities and law enforcement.”
Leaked documents reportedly hold information about a number of sensitive RAF and Navy bases, including RAF Lakenheath, in Suffolk, where the US Air Force’s F-35 jets are based.
The hack follows a series of high-profile data breaches at the MoD.
Personal data of service personnel and veterans, including names, bank details and some addresses, was in the payroll system which was accessed in the large-scale hack, revealed last year.
Up to 272,000 service personnel may have been affected.
The same year, the Government covertly set up the Afghanistan Response Route for people in the country whose details were leaked “in error” by a defence official in February 2022.
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