LLMs’ Data-Control Path Insecurity

Someday, some AI researcher will figure out how to separate the data and control paths. Until then, we’re going to have to think carefully about using LLMs in potentially adversarial situations—like on the Internet.

Back in the 1960s, if you played a 2,600Hz tone into an AT&T pay phone, you could make calls without paying. A phone hacker named John Drapera noticed that the plastic whistleb that came free in a box of Captain Crunch cereal worked to make the right sound. That became his hacker name, and everyone who knew the trick made free pay-phone calls.

There were all sorts of related hacks, such as faking the tones that signaled coins dropping into a pay phone and faking tones used by repair equipment. AT&T could sometimes change the signaling tones, make them more complicated, or try to keep them secret. But the general class of exploit was impossible to fix because the problem was general: Data and control used the same channel. That is, the commands that told the phone switch what to do were sent along the same path as voices.

Fixing the problem had to wait until AT&T redesigned the telephone switch to handle data packets as well as voice. Signaling System 7c—SS7 for short—split up the two and became a phone system standard in the 1980s. Control commands between the phone and the switch were sent on a different channel than the voices. It didn’t matter how much you whistled into your phone; nothing on the other end was paying attention.

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