Bloomberg reports that computer hackers working through Internet servers in China broke into and stole proprietary information from the networks of six U.S. and European energy companies, including Exxon Mobil Corp., Royal Dutch Shell Plc and BP Plc, according to one of the companies and investigators who declined to be identified. McAfee Inc., a cyber-security firm, reported Feb. 10 that such attacks had resulted in the loss of project-financing information with regard to oil and gas field bids and operations. In its report, McAfee, assisted by other cyber-security firms, didn’t identify the energy companies targeted. The attacks, which it dubbed "Night Dragon," originated primarily in China and occurred during the past three years. The list of companies hit, none of which disclosed the attacks in filings with regulators, also includes Marathon Oil Corp., ConocoPhillps and Baker Hughes Inc., according to the people who worked on or are familiar with the companies’ investigations and asked not to be identified because of the confidential nature of the matter.