The phenomenon of SIM farms, even at the scale found in this instance around New York, is far from new. Cybercriminals have long used the massive collections of centrally operated SIM cards for everything from spam to swatting to fake account creation and fraudulent engagement with social media or advertising campaigns. The SIM cards are typically housed in so-called SIM boxes that can control more than a hundred cards at a time, which are in turn connected to servers that can then control thousands of SIMs each.

SIM farms allow “bulk messaging at a speed and volume that would be impossible for an individual user,” one telecoms industry source, who asked not to be named due to the sensitivity of the Secret Service’s investigation, told WIRED. “The technology behind these farms makes them highly flexible—SIMs can be rotated to bypass detection systems, traffic can be geographically masked, and accounts can be made to look like they’re coming from genuine users.”

The telecom industry source adds that the images of SIM servers and boxes published by the Secret Service indicate a “really organized” criminal operation may have been behind the setup. “This means that there is great intelligence and significant resources behind it,” the person added.

The SIM farm found by the Secret Service, Unit 221b’s Coon says, isn’t the biggest operation he’s learned of in the US. But it’s the most concentrated in such a small single geographic area. SIM boxes, he notes, are illegal in the US, and the hundreds of them found in the Secret Service’s investigation must have been smuggled into the US. In one case he was involved in, Coon says, the boxes were imported from China, disguised as audio amplifiers.

The “clean, tidy racks” of equipment in a well-lit room shows that the operation may be well-organized and professional, says Cathal Mc Daid, VP of technology at telecommunication and cybersecurity firm Enea. Photos released by the Secret Service show multiple racks of telecom equipment neatly set up, with individual pieces of tech numbered and labeled, plus cables on the floor being covered and protected with tape. Each SIM box, Mc Daid says, appears to include around 256 ports and associated modems. “This looks more professional than many of the SIM farms you see,” says Mc Daid.

Mc Daid notes, however, that he’s tracked similar operations discovered in Ukraine—some of which have been as large or even larger than the one revealed on Tuesday by the Secret Service. Over the course of the last few years, law enforcement officials in Ukraine have discovered tens of thousands of SIM cards being used in SIM farms allegedly set up by Russian actors. In one case in 2023, around 150,000 SIM cards were reportedly found. These SIM farms have been used to operate fake social media profiles that can spread disinformation and propaganda.