How cell calls and text messages are intercepted: are you concerned yours might be?

Those are the good intercept guys. But that doesn't represent the entire cell phone intercept universe.
Written by Russell Shaw, Contributor

Those are the good intercept guys. But that doesn't represent the entire cell phone intercept universe.

The odds are vanishingly small that anyone is actually out there intercepting your text messages. But that doesn't mean it cannot be done.

In fact, an article posted last week to the online magazine Slate describes how both the good people and bad people do it.

Bad people as in criminals, and good people as in law enforcement trying to catch these criminals.

The first way is phone cloning. With this method, incoming messages can be intercepted and outgoing ones can be sent as if from your won phone. The bad guys make copies of your SIM card. They do this via SIM readers that can read your cards crypto key. Then the SIM card is transferrable to another phone.  

By the way, punishment for doing this is substantial. And, there's no firm guarantee that the phone's encryption won't be overly sophisticated.

These criminals also can do the dirty deed by uploading very, very illegal firmware onto your phone. As Slate's Christopher Beam (apt name, considering the subject, huh)? explains:

This (use of firmware) essentially turns your phone into a radio and allows it to pick up all the texts broadcast on a given channel—instead of limiting you to the ones addressed to you. You'd also need to know the network for the target phone—Verizon, Cingular, T-Mobile, etc.—and you'd have to make sure that both your phone and the target are within range of the same base station. This method isn't too expensive since you don't need much more than a computer, a phone, and some firmware that any serious techie could find online for free.

Yes, Chris, but how do they do it on shows such as CSI:Miami?

Well, if the plotline were real,they would use something like Cellular Monitoring GSM Intercept model GSM 2060TP for (hey, guess what) GSM networks, and Cellular Intercept (CDMA).

When we visit the website of Securities Intelligence Technologies Group, we don't learn all that much about either of these solutions. That's understandable, because we don't want the drug dealers and terrorists to know how we track them. Info is available, but only for registered users (ideally law enforcement types).

Here's what the company site tells us about the CDMA intercept solution:

"This cellular intercept system operates by automatically detecting the strongest signal in a CDMA service area. Working as a mobile phone intercept on global CDMA networks, the CDMA Cellular Monitor also intercepts control channels and both sides of a conversation through traffic channels."

Less specific info is offered about GSM intercept, but with relation to general intercept capabilities, we learn that: 

"All of the decryption technology is built into HSS Cellular Intercept Systems, therefore, no connection into any cellular phone network is required (as it is when using hardwire junctures or non “off the air” monitoring systems).  In addition, the audio digital recording capabilities in HSS Cellular Intercept Systems are also user friendly."

In other words, powerful decryption for text, and audio recording for intercepted voice.

User-friendly, but not budget-friendly. At least insofar as law enforcement use is concerned,  Slate mentioned that some of these solutions can cost in the $1 million range.

But SIM readers? Go Google it or eBay it. Much cheaper. Less than a tank of gas in most places.



Although there are some legitimate uses for these tools (such as enabling transfer of data from one cellphone's SIM card to another) the folks who use these tools to intercept cell calls and texts have something more wicked mind.

Are you concerned?

[poll id=55]


Editorial standards