Ukrainian intelligence agency steals Russian nuclear sub secrets in a cyber attack
By Sean Rayment
Ukrainian spies claim to have stolen classified data on Russia’s newest nuclear missile submarine during a recent cyber operation.
The secret Russian data allegedly includes details about the vessel’s vulnerabilities—likely to be highly valuable to Western navies.
Cyber specialists working for Ukraine’s military intelligence agency, the HUR (Main Directorate of Intelligence), reportedly breached the Russian Navy’s systems and obtained internal documents concerning the new Project 955A Borei-A-class submarine Knyaz Pozharsky, which entered service less than two weeks ago.
The HUR specialists reportedly obtained a list of the submarine’s crew, including information on their positions, fitness levels, and combat instructions, as well as technical data on the boat’s layout, such as diagrams of its survivability systems.
Details of the cyberattack were revealed by the intelligence agency in a public statement. To support its claims, the HUR published several documents that appear to have been obtained during the breach.
The agency said its operatives also accessed crew regulations, instructions for transferring wounded sailors and cargo, engineering documentation, towing procedures, and the submarine’s operational schedule.
The Ukrainian intelligence operation could represent a significant setback for the Russian Navy, exposing vulnerabilities within its Project 955A-class submarines—a key component of Moscow’s nuclear triad, alongside ground- and air-launched nuclear missiles. These submarines are considered among the most advanced in Russia’s fleet.
“The information obtained by the intelligence allows identification of the features and technical limitations not only of Knyaz Pozharsky but also of other submarines in the Project 955A series, which are critically important for maintaining the imperial myth of the aggressor state Russia,” the HUR wrote in a recent Telegram post.
Russia operates one of the largest submarine fleets in the world, with an estimated 64 active vessels, including five of the improved Project 955A “Borei-A” class variants.
These stealthy, nuclear-powered submarines are 170 metres long and can travel at speeds of up to 29 knots (33 mph) when submerged. Each Project 955A submarine, including Knyaz Pozharsky, is capable of carrying 16 RSM-56 Bulava submarine-launched ballistic missiles (SLBMs), each equipped with nuclear warheads.
The RSM-56 Bulava is a three-stage, solid-fuel intercontinental ballistic missile that has been in service since 2013. It has an estimated range of over 8,000 kilometres and can carry up to 10 independently targetable warheads, each with a yield of 100 to 150 kilotons. The submarines can also carry up to 12 torpedoes.
Construction of Knyaz Pozharsky began in 2016. The vessel was officially commissioned into service on 24 July 2025, at a ceremony attended by Russian President Vladimir Putin. It has joined the 31st Submarine Division of Russia’s Northern Fleet, based in Gadzhievo, in the Murmansk region.
Russian submarine and underwater activity—particularly in the Arctic—has increasingly become a focus for NATO. Just last week, for example, the alliance announced the deployment of a maritime task force to operate in the High North as part of its efforts to bolster its presence in the region.
