Suppose your phone is not connected to any network. You are sitting in a cafeteria with 50 other people, everyone is communicating to each other via text messages. Is it possible through any device or way to capture messages within that field?

1 Answer 1


Yes. A Harris Stingray, Boeing DRT box, or other cell simulator can intercept SMS messages.

These are monitoring devices that have secretly been used by police agencies for over a decade. They come with strict non-disclosure agreements where the agencies that purchase them are not even allowed to acknowledge their existence to the public, and certainly are not available to the general public. As they have recently come into the sunlight, the legality of their use for warrantless wiretaps has been called into question. The state of California passed a law that took effect on 1 January, 2016, requiring officials to obtain a warrant to use them.

Researchers have used a cheap RTL-SDR receiver to decode SMS messages; be aware this would likely run afoul of various laws if applied to any messages but your own. If you're interested, here is a link to the project writeup.

  • very informative, sorry coudln't upvote since I am new and reputation is low. Is there any link for purchasing this device ? Do I need license from government to operate it ?
    – Johnny
    Jan 29, 2016 at 6:53
  • 1
    Those links list off some common hardware devices and open source software tools the person used to decrypt GMS messages. You can buy the rtl-sdr sticks online by searching the web, they're fairly inexpensive. The software is free. Learning how to use it would certainly be the most difficult part of the task. And I don't know where you are from, but many governments have laws strictly prohibiting intercepting phone or SMS traffic without a warrant issued by a judge. There are no licenses that grant authority to snoop on other people's phone calls without their permission! Jan 29, 2016 at 7:38
  • I believe Vice news was almost able to buy a stingray from Hong Kong
    – BadSkillz
    Jan 29, 2016 at 8:15

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .