Chinese hackers are breaching Navy contractors to steal everything from ship-maintenance data to missile plans, triggering a top-to-bottom review of cyber vulnerabilities, WSJ reported Friday, citing officials and experts. From the report: A series of incidents in the past 18 months has pointed out the service’s weaknesses, highlighting what some officials have described as some of the most debilitating cyber campaigns linked to Beijing. Cyberattacks affect all branches of the armed forces but contractors for the Navy and the Air Force are viewed as choice targets for hackers seeking advanced military technology, officials said. Navy contractors have suffered especially troubling breaches over the past year, one U.S. official said. The data allegedly stolen from Navy contractors and subcontractors often is highly sensitive, classified information about advanced military technology, according to U.S. officials and security researchers. The victims have included large contractors as well as small ones, some of which are seen as lacking the resources to invest in securing their networks. One major breach of a Navy contractor, reported in June, involved the theft of secret plans to build a supersonic anti-ship missile planned for use by American submarines, according to officials.