Europe’s Defence Giant Naval Group Hit by Major Cyber Breach

Naval Group, France’s largest shipbuilder and a key player in European defense, has allegedly suffered a major cyberattack. A threat actor posted claims on a popular data leak forum, asserting access to sensitive materials, including source code for combat management systems (CMS) used in French submarines and frigates.

The Paris-headquartered Naval Group, employing over 15,000 people and generating annual revenue of more than $5 billion (€4.3 billion), is primarily owned by the French government and Thales Group. The breach, considered one of France’s largest defense-related data compromises, poses serious national security concerns. Hackers are not attempting to sell the data but are reportedly extorting the company, threatening to leak classified material unless demands are met.

According to the attackers, the stolen data includes CMS source code, internal network details, technical documents, developers' virtual machine access, and confidential communications. Some leaked media, such as submarine footage from 2003, has also surfaced. If verified, the breach could offer adversaries critical insights into France’s naval capabilities, requiring significant investment to counter.

Thales, a key shareholder, risks reputational damage and operational disruptions. Dassault Systèmes, which provides software like the 3DExperience platform to Naval Group, may also face scrutiny over software integrity and cybersecurity readiness.

Cybersecurity experts caution that attackers may exaggerate the breach’s severity to pressure victims into meeting extortion demands. While the true extent remains unconfirmed, researchers suggest the leaked sample includes authentic data.

Founded in the late 17th century, Naval Group has long been integral to French naval defense. Notably, it built France’s only nuclear aircraft carrier, Charles de Gaulle, under its former name DCN (Direction des Constructions Navales).

French authorities are now actively investigating and responding to the breach.