John Bumgarner, chief technology officer with the U.S. Cyber Consequences Unit added: "It is highly troubling that the military computer systems used to fly classified Predator missions were breached by an unknown adversary. The security controls for these sensitive national security systems should have been held to a much higher standard by the Department of Defense."

Despite the sensitive nature of their operations, computer security hasn't been a hallmark of drone operations. In 2009, for example, the military seized the laptop of a Shiite militant in Iraq and found days of video footage intercepted from drones flying missions in the region. Since video feeds from the drones are unencrypted, , it's relatively easy for the militants to snatch them from the air with software that can be purchased off the Internet for $26.

Since the terrorist attacks on the United States on Sept. 11, 2001, drones have increased in importance as a tactical weapon. In the 10 years following 9/11, 30 CIA drones have been attributed with the deaths of . Another 150 Predator and Reaper drones operated by the Air Force patrol the skies over Iraq and Afghanistan. U.S. drones were also used to support NATO air attacks in Libya and were responsible for the death last week of Anwar al-Awlaki, dubbed by some as the "Osama of the Internet."

[Updated Oct 7, 4:04 PM with additional information]

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