A group of hackers has yet again managed to infiltrate the firmware inside the Pentagon and to get away with an undisclosed number of terabytes of sensitive data. It's not yet clear who has been behind the infiltration, but the US government and publications such as the Wall Street Journal have already begun to point fingers at the Chinese. Representatives of the Asian nation have vigorously rejected the accusations and say that the Chinese government didn't order or support any such action.

The Chinese Embassy has told in a statement that China “opposes and forbids all forms of cyber crimes.” It has called the Pentagon report “a product of the Cold War mentality” and has added that the allegations of cyber espionage are “intentionally fabricated to fan up China threat sensations,” the Wall Street Journal reports.

According to US officials, the data that was stolen was all related to the F-35 joint strike fighter airplane, which is, to this date, the most costly project the Pentagon has ever gotten involved in. However, the spokespersons also share that the hackers didn't manage to steal the most sensitive data about the plane, which was, most likely, their objective. That information is stored on non-networked, secured computers, and the location of these machines is classified.

The hackers apparently used some vulnerabilities they encountered on the websites of some contractors that were helping with the construction of the $300-billion project. They employed a tool that encrypted data as it was being stolen, so officials couldn't immediately realize what was being defrauded. They do know what's still there, as in the diagrams and codes for the navigation system and the sensors, which are separately stored.

This is the second successful attack on the Pentagon in just a few weeks, and it would seem that the people in charge of the institution's defenses are not very good at their job. If every attack on its firmware succeeds, then something is clearly amiss.