[TurdF3rguson]

I heard he can launch nukes by whistling into a pay phone.

[jagged-chisel]

Maybe I'm mistaken, but that sounds more like Chuck Norris.

Wait ... no fists involved. My mistake.

[alex1138]

It's in his (Mitnick's) autobiography Ghost in the Wires. In his telling of the story they put him in a more restrictive environment exactly because of the reason given (launching nukes by whistling into a phone)