That's a pretty clever way to be very stupid! Anyone who reports the message (forward it to 7726, spells SPAM) to a network tips the network off that messages are landing on subscribers devices that didn't come through their system.
And I guarantee there are devices listening into, characterising and locating radio emitters in major cities at the very least.
I like the fact that some of the earliest mappings had 0 mapped to "OPER" ("Operator"), because it makes me imagine that this number 33700 is like some interpretation of 337 and then shouting twice for the "operator" (as in, the literal physical person that used to sit and connect calls using wires and a patch board).
Taking this further then, and given that:
- 3 is assigned to any of the three letters DEF, and
- 7 is assigned to any of the three letters PRS,
we could invent the following meaning:
DES = "Déclaration d'Envoi de Spam". (Lit. "Declaration of sending of spam", as in a report about spam sending).
The double 0 is, as mentioned, in our invented meaning like shouting "Operator! Operator!"
And with this invented meaning it's like we are shouting for help from the operator to deal with this spam :D
Of course here I'm starting with 337 and backronyming "DES" to a plausible but probably weird sentence. If it was a real, the French would probably have worded the original sentence quite differently and the resulting number would be different as well.
(Also, looking at the article I'm not sure if any European countries also had 0 used for "OPER" or not. Guess I'll have to travel to some museums in France and have a look at some old phones with my own eyes at some point.)
I don't know if it was involved here, but "spectrum monitoring" (that's the keyword for more information about equipment you can get and who the expected customers are) is definitely a thing that is done in many places, and not only by the military, but also by police and regulators. It's not clear where the mast was installed (the CoL police aren't specifically limited to that very small area and one arrest was South London and one was Manchester) but if it was in central London, as a glaring terrorist target with an airport (London City) and heliport, I'd be very, very surprised if there's nothing watching the spectrum. Whether the operators of the spendy gear would share the information up for such "petty" crime, I don't know.
And there's always the Ham community who really, really hate spectrum abusers.
Come to think of it, the mobile operators themselves have a large national network of radio receivers with lots of fancy time-of-flight, phased array multi-path, multi-band capabilities.
Maybe these days Ofcom can just ask them if they are interested in something specific.
I don’t think spectrum monitoring capability is all that secret. Certainly anyone with the knowledge to set up their own BTS should recognize the possibility they could be triangulated.
Yeah if you run a private antenna either the police or some men from your country's equivalent to FCC will come to your door and politely ask you to stop, if they are having a good day, most likely confiscate some of the equipment as well. And that's just for emitting anything on reserved spectrum or with too much power, not even for crime.
The Polish democratic opposition used to do this in the 80's, during the communist era. As far as I remember, their technique relied on balloons, they would attach a homemade antenna and tape player to a balloon, set it on a timer and release the balloon into the air. Before the transmission started, they'd be long gone and the balloon would have drifted far from the original site, making the perpetrators much harder to track down. As a bonus, they'd get an antenna high up in the air (which is good for reception), which was also hard to disable, even if you managed to pinpoint its location.
Listening isn't illegal so you can do that without moving. People move just to listen to different things with limited range, one form of it is called wardriving if you're doing it to wifi for example.
You can't send a phishing SMS from a receive-only device. Any mobile tower must have an active transmitter (at the very least, so the handset knows what network it thinks it's connected to!).
Transmitting on a licensed mobile service band without the license is a very good way to earn a knock on your door.
Eavesdropping on tower-to-handset comms is illegal too (in the UK), but it's not very practical to find just a receiver, unless they already know almost exactly where it is and are able to do a TEMPEST-like attack on the local oscillator or something. So as long as you keep quiet and don't do anything to indicate you're listening, such as, posting on Twitter about it or you do crime based on it, you'll get away with it. However, a receiver can't bump a victim handset down to a primitive-enough protocol, so all you'll get is encrypted content and maybe a smidge of metadata (I'm not sure exactly what is and isn't encrypted for each "G").
That's not true - it is indeed illegal to listen in to radio transmissions which are not intended for you. Doing so is a criminal offence punishable by an unlimited summary fine (the precise amount is determined based on the offender's personal income and other circumstances).
I'm fairly sure in the UK it's illegal, tho I don't know for certain. But even if not, you could be arrested for conspiracy to commit fraud (or similar).
And I guarantee there are devices listening into, characterising and locating radio emitters in major cities at the very least.