Hackers may have gotten close to sensitive data on the Pentagon's $300 billion Joint Strike Fighter Project, but they failed to get their hands on highly sensitive data, according to the Pentagon and a defense contractor.

Computer intruders have infiltrated the project's less sensitive systems, but the highly classified data has been protected, according to the Pentagon and Lockheed Martin, the lead defense contractor for the new F-35 Joint Strike Fighter.

The Joint Strike Fighter is the most sophisticated program the Pentagon has ever attempted. It relies on more than 7.5 million lines of computer code. And reports that the system had been hacked raised loud alarms in the intelligence and IT communities.

"We know we are probed on this every day," said Pentagon spokesman Bryan Whitman. "We have very aggressive defensive systems. The more sensitive the information, the greater the safeguards are." He added that he was not aware of any sensitive F-35 technology having been compromised by a cyber attack.

For more on the hack alarm:
- check out this Washington Post article