The Max Headroom signal intrusion hack is one of those hacker legends that seems too good to be true: In 1987, an unknown group hacked into the signal of local Chicago TV channel WGN-TV. 25 years later, Vice's Motherboard blog has published a fascinating investigation into who pulled off the still unsolved crime.

The hack, which is viewable on YouTube, interrupted a broadcast of the nine o'clock news at 9:14 PM on November 22nd, 1987. The picture was replaced with a man babbling in front of a camera wearing a Max Headroom mask. (Max Headroom was a cult fictional British VJ.) Vice's Chris Knittel obtained FBI files and interviewed former investigators about the crime.

From Motherboard:

In the case of the Max Headroom intrusion, the theory goes like this: the hacker managed to overpower the microwaves of the STL, which sat vulnerable to attack on a frequency that wouldn't have been hard to find, as they were being sent to the receivers atop the John Hancock Building and Sears Tower.

The intruders would have simply had to switch on their transmission equipment at a high enough location, probably a high-rise apartment or a roof, at a place between the two studios and their downtown transmitters, somewhere on the North or Northwest Sides of Chicago. From there, they could blast the skyscraper receivers with high-power microwave frequencies, and by overriding the studios' signals, they could trick the transmitters into sending out their own signal. "I think the bad guy got close to the receiving end and just transmitted a signal that was received with a stronger strength than the more distant, intended signal," said Marcus.

In the end, the only real lead Knittel found was a Redditor to have met those responsible through the Chicago online bulletin board scene in the 80s. But the whole story is a fascinating and much-overdue dig into a piece of hacker lore. Read the whole thing.