The United States' most expensive weapons program has been breached by spies, according to the Wall Street Journal, with the Joint Strike Fighter project the victim of cyber intrusion.
The $300 billion project, which is being headed up by Lockheed Martin, with Northrop Grumman Corp and BAE also involved, has reportedly seen hackers take advantage of vulnerabilities in two of the three contractors' networks.
The report in WSJ quotes inside sources that reveal the security breach, which saw information siphoned off.
The Pentagon project apparently kept the most critical information in other un-networked computers, so the entire project will not be sidelined by the lapse in security.
The Pentagon refused to comment directly on the matter.
This is just the latest in the increasingly publicised rise of cyber-spying, where specific companies and government offices are targeted for modern day espionage.