Governments use them to track phones. Criminals drive them through city streets and send texts that look like they came from your bank. For 20 years, researchers have been building tools to catch these fake cell towers. They have tested those tools mostly against fake towers they built themselves.

That loop has left gaps. Researchers at KAIST built a platform called Devilray that reproduces 2,592 distinct fake-base-station behaviors. They ran it against seven existing detection systems, and every one of them missed at least 192. The finding points to a larger problem with how the field tests itself: detectors have been evaluated against the wrong adversary.

The work is published on the arXiv preprint server.