KYIV — A Ukrainian hacking collective known as Ukrainian Militant has claimed that it obtained a large collection of Russian naval technical documents during a cyber operation it calls “Poseidon.” The group says the material covers around 70 Russian naval projects, including submarines, surface ships, navigation systems, sonar and marine robotics.
The group announced the operation around September 20, 2026, and released screenshots and samples of documents that it says came from Russian defense-industrial organizations. Some of the documents are reportedly marked “secret” or “top secret,” with materials dated as recently as 2026.
Documents Cover Submarines and Surface Ships
According to Ukrainian Militant, the leaked material relates to scientific, engineering, testing and operational work supporting Russian naval construction and modernization.
The projects identified by the group include the Project 949AM Antey nuclear-powered submarines, Project 636.3 Varshavyanka diesel-electric submarines and Project 955M, associated with the Borei-A ballistic missile submarine program.
The released material also concerns surface ships from Projects 22350, 20386, 23550, 11711, 23770 and 23900.
The documents are described as containing information on the placement of onboard equipment, cable connections, information interfaces, structural and functional diagrams, technical requirements, operating procedures, testing methods, accuracy and reliability specifications, and acceptance documentation.
One of the examples cited by the group is documentation related to the Simfoniya-PM navigation system, including testing material from 2026.
Focus on Navigation and Underwater Systems
A significant part of the reported archive concerns naval navigation and underwater technologies.
The material covers inertial navigation, radio navigation, sonar or hydroacoustics, integrated control systems, digital hydrography, mapping and marine robotics.
Some of the documents concern autonomous navigation systems for submarines and underwater vehicles. Such systems are designed to support navigation without relying solely on satellite positioning signals.
Ukrainian Militant identified several systems and development programs in the released material, including Simfoniya, Simfoniya-PM, Chardash-22350, KAMA-NS-VK, Sprut-N1, Priliv, 14Ts217, AKNG/PNG-23820 and ISU NK-23550.
The group also listed prospective research and development programs including Kasatka, Veter, Bering, Dirizhor, Poligon, Andromeda, Arkhivarius, Almukantarat and Seagull-M (Sigal-M).
Documents dated between 2024 and 2026 have reportedly appeared among the released samples, including material concerning the Andoga-M2 navigation complex for Project 636.3 submarines.
Russian Defense Organizations Named
The hackers said the documents are connected to several Russian organizations involved in naval design, navigation and underwater technologies.
These include the Rubin Central Design Bureau for Marine Engineering, Malachite Marine Engineering Bureau, Elektropribor Central Research Institute, Okeanpribor concern, Elara, the Vega concern and the State Research Navigation and Hydrographic Institute (GNINGI).
The reported documents also provide information on cooperation between contractors, research and development activities, testing programs and the status of individual projects.
Full Scope of the Breach Not Independently Verified
The claim that the operation compromised information from 70 naval projects has not been independently verified in full.
The open-source intelligence organization InformNapalm has examined screenshots and individual documents released by Ukrainian Militant and confirmed the existence and authenticity of some documents showing details of Russian military-related organizations. However, the group has not received the complete archive from the hackers because of operational-security restrictions.
As a result, the full size of the stolen data, the exact number of affected projects and the depth of the reported network penetration cannot currently be independently established.
The reported breach comes amid a series of cyber operations targeting Russia's defense sector. In November 2025, Ukrainian-linked hackers also claimed to have obtained classified material associated with Russia's PAK DA strategic bomber and Su-57 fighter programs.
Ukrainian Militant has primarily published information about Operation Poseidon through its Telegram channel, while Ukrainian and independent media outlets have reported on the claims using the group's statements and released document samples.
——— End of Article ———
