A hacker group has claimed responsibility for a cyberattack targeting France’s state-owned Naval Group, one of the country’s most important military shipbuilders. The attackers say they have already released 30 gigabytes of information and are threatening to publish more, claiming the stolen files include highly sensitive military details.
Naval Group designs and builds advanced naval vessels, including France’s nuclear-powered Suffren-class submarines and the nation’s only aircraft carrier, the Charles de Gaulle. The company plays a key role in France’s defense capabilities and is a major supplier to NATO allies.
According to the hackers’ statement on a dark web platform, the stolen material includes information on submarines, frigates, and possibly source code for submarine weapon systems. They allege they hold as much as one terabyte of data and have given the company 72 hours to confirm the breach.
Naval Group has rejected the claim that its internal networks were hacked. In a statement, the company said it “immediately launched technical investigations” after the material appeared online and described the incident as a “reputational attack”— suggesting the goal may be to damage the company’s public image rather than disrupt operations. The firm stressed that so far, there is no evidence of unauthorized access to its systems or any impact on its activities.
The leaked 30GB of files, if authentic, could contain sensitive information related to France’s nuclear submarine program, which is central to the country’s national security strategy. Naval Group, which is nearly two-thirds owned by the French government, employs over 15,000 people and generates annual revenues exceeding €4.4 billion.
Cybersecurity experts note that military contractors worldwide have increasingly become targets for cyberattacks, as they store valuable data on defense technology. The case comes shortly after other high-profile breaches, including Microsoft’s confirmation that certain vulnerabilities in its SharePoint servers remained exploitable, and an intrusion at the U.S. National Nuclear Security Administration, which oversees America’s nuclear arsenal.
Naval Group says all of its technical and security teams are currently working to confirm the authenticity, origin, and ownership of the published data. Investigations are ongoing, and French authorities are expected to monitor the situation closely.
