Smartphones·1,349 discussions

Does swapping a SIM card work?

Locked

In the movie 12 Rounds, the villain continually eludes police tracers by swapping out the SIM card in his cell phone.

Was wondering if that could really work.

NO, I’m not considering it for real-life, I’m writing a story and need a way to avoid being traced in a cell-phone conversation. Several times.

In case you’re interested, the story is here: http://www.associatedcontent.com/article/1926550/serial_scifi_novel_those_who_dwell.html

Feel free to read and comment. 🙂

Topic

IDK

In reply to Does swapping a SIM card work?

If they tracked on “hardware address” (IMEI), then it wouldn’t work. The SIM card (IMSI) stores only the subscriber information, so theoretically, you’d only change the phone number not the “address” of the phone.

My intial instinct would be no…

In reply to Does swapping a SIM card work?

…since not all Telecom providers require SIM cards. I’d imagine they’re getting tracked by either the GPS or IMEI information.

However, I am not a cellular expert by any means, so I could be as wrong as a ‘S’ is crooked.

As for the story, I’ll try and give it a read this weekend; provided the teething baby settles down enough for it to happen! 😉

EDIT: In terms of the story, you could always have the perp save his contacts to a SD card, and just plug that into a variety of disposable phones as he/she goes; assuming the saved numbers is why the phone itself wouldn’t be getting pitched.

Ok so how DOES police tracing work?

In reply to My intial instinct would be no…

on the movies they either trace the actual phone# or the cell phone location based on what towers it’s bouncing off of.

What’s the low down on HOW that sort of tech works?

Actually it’s not a criminal or villain that needs to be untraceable. It’s a good guy(s) that needs to hide from a government research agency.

If they are tracing by active transmission…

In reply to Ok so how DOES police tracing work?

then all the phone user has to do is end the call. The character would probably have an idea of how long that would take, on average. Just keeping calls short would work.

Disabling the GPS/911 feature would prevent locating the phone through the GPS-enabled location system.

For the truly paranoid types, they would have the GPS-related hardware bits damaged, assuming this doesn’t otherwise break the phone.

I suppose a case could be made for having the cellular provider hacked so that searches for the phone would be misdirected.

(No research done here.)

A quick glance at the story – looks interesting.

Why not

In reply to If they are tracing by active transmission…

VoIP transmissions over wifi and routed through a TOR network. Between short calls and the difficulty of backtracing the call through TOR he could bounce from hotspot to hotspot remaining several steps ahead.

Aye.

In reply to Why not

I was wondering about the possibilities of VOIP in itself. I’m just not well-versed enough to know whether one could be tracked through the VOIP account, and how a phone call would leave the VOIP network at the other end in the case that the call was to a non-VOIP phone.

Not quite right

In reply to If they are tracing by active transmission…

To locate the phone, it must emit at least the roaming signal to contact the next nearby antenna tower, but the process does not require an active call.

The following is from my notes, not sure where I got them though:

Locating systems can be broadly divided into network based, handset-based, and hybrid:

Network-based techniques utilize the service provider’s network infrastructure to identify the location of the handset. The advantage of network-based techniques (from mobile operator’s point of view) is that they can be implemented non-intrusively, without affecting the handsets.

Handset-based technology requires the installation of client software on the handset to determine its location. This technique determines the location of the handset by computing its location by cell identification, signal strengths of the home and neighboring cells or the latitude and longitude, if the handset is equipped with a GPS module. The calculated location is then sent from the handset to a location server.

Hybrid-based techniques use a combination of network-based and handset-based technologies for location determination. One example would be Assisted GPS, which uses both GPS and network information to compute the location. Hybrid-based techniques give the best accuracy of the three but inherit the limitations and challenges of network-based and handset-based technologies.

Examples

Cell Identification – The accuracy of this method can be as good as a few hundred meters in urban areas, but as poor as 32 km in suburban areas and rural zones. The accuracy depends on the known range of the particular network base station serving the handset at the time of positioning.

Enhanced Cell Identification – With this method, one can get a precision similar to Cell Identification, but for rural areas, with circular sectors of 550 meters.

U-TDOA – Uplink-Time difference of arrival – The network determines the time difference and therefore the distance from each base station to the mobile phone.

TOA – Time of arrival – Same as U-TDOA, but this technology uses the absolute time of arrival at a certain base station rather than the difference between two stations.

AOA – Angle of arrival – AOA mechanism locates the mobile phone at the point where the lines along the angles from each base station intersect.

E-OTD – E-OTD is similar to U-TDOA, but the position is estimated by the mobile phone, not by the base station. The precision of this method depends on the number of available LMUs in the networks, varying from 50 to 200 m.

Assisted-GPS – A largely GPS-based technology, which uses an operator-maintained ground station to correct for GPS errors caused by the atmosphere/topography. Assisted-GPS positioning technology typically falls back to cell-based positioning methods when indoors or in an urban canyon environment.

You will have Tink!

In reply to Not quite right

Writing like Tom Clancy, if she can get by all the other stuff.

Whew!

In reply to Not quite right

Definitely what I was looking for! Now to sort it all out in my brain.

Thanks for this Michael!

Awesome, as always.

In reply to Not quite right

That is a fantastic bit of information.

Each time you swap the sim card

In reply to Does swapping a SIM card work?

you will have to call the provider and activate the new sim.

I’m thinking

In reply to Each time you swap the sim card

that for the purposes of the story, the activating part has already been done.

But hey, I’m not a screenwriter, so what do I know? 😉

That would make sense

In reply to I’m thinking

but still, the same IMEI and you would have to come up with a identity for each sim.

True

In reply to That would make sense

But it’s only a movie after all.

I automatically suspend disbelief at the movies. I can almost guarantee that every action or suspense movie will have one or more technical inaccuracy or impossibility, I suspect because it either “supports the story” or is simply needed to add visual impact (e.g. every car in every crash explodes in flames).

Why? To paraphrase, “Dammit, MJ, I’m a technician, not a screenwriter!” :p

Identity?

In reply to That would make sense

You can buy them cheap down at the DMV I hear…

Seriously, many cell providers have prepaid services where you don’t even need a credit card to sign up. Surely the folks who creat fake drivers licenses would know the guys wanting to get untraceable disposable cellphones.

James

Pre loaded disposable sims?

In reply to Each time you swap the sim card

or, pay-as-you-go, as they call them over here.

And yes, the sim has to be activated to whichever provider.

Oh, and everything that Mike Kassner said up there ^^^ too.

Watch out for the legal side of tracing – if your character is in the UK or EU, I can sort you out with the legals on that. If he’s in the US, you need to check out what it takes to trace over there.

Remember, it’s easier to swop the sim than the phone. Take it from me, even though they all look, well, similar, you get used to your own model of phone fairly quickly.

(oh, and you forget quickly too – got Ma a cell the same as my last one; she keeps asking questions, and I keep forgetting how it works…… and I’ve only had the smartphone two months! 🙂 )

Peer me if I can help, Tink.

Right, off to have a read….. 😀

GG

Probably

In reply to Does swapping a SIM card work?

about as well as sex change operations.

Why not just buy a throwaway cellphone each time ??…

In reply to Does swapping a SIM card work?

That would be the easiest way to avoid being traced surely??!!

Cellphones are so cheap these days, this character could have a few ‘calls’ supply stuffed in a suitcase. 😉

I did think of using disposables

In reply to Why not just buy a throwaway cellphone each time ??…

That was my first thought. The good guy’s contact was going to messenger him a box of disposables to use to contact her.

Was just trying to figure out a less bulky method. 🙂

Okay, Tink

In reply to Does swapping a SIM card work?

I (finally) went and began reading it.

I read with a blue pencil.

I am reminded of how much has been written over the ages about first words of the first sentence of a piece.

Aspire to that.

You mean like

In reply to Okay, Tink

It was a dark and stormy night…

No all wrong.

At least Snoopy

In reply to You mean like

Didn’t say, “It was a very dark and stormy night…”

Just what did Snoopy say

In reply to At least Snoopy

Curse you red barron or something like that.

As I recall he was always trying to write something, was he ever successful?

No

In reply to Just what did Snoopy say

But I think Snoopy was the impetus for a writing competition — a camp writing competition, for which prizes are given to the worst offenders.

All I really remember

In reply to No

is the reference to the little red haired girl.
She still haunts me.

Let’s not go there

In reply to All I really remember

I had one of those.

I still do ~NT~

In reply to All I really remember

.

That would be the Bulwer-Lytton Contest

In reply to No

Contestants are asked to “compose the opening sentence to the worst of all possible novels.” http://www.bulwer-lytton.com/

Bulwer-Lytton is the one who started his novel with “It was a dark and stormy night.”

Santee

In reply to Okay, Tink

Ok, I admit, the first line isn’t a “grabber” per se but do you know how hard it is to come up with a beginning for someone walking into a psychiatrist’s office? LOL.

I hated those classes that dwelled on the first line. Bah! If I want to start with a doggone “THE” I’ll start with a “THE”! Especially if it fits the story! 😀

“Call me, Ishmael.”

In reply to Santee

Okay. Forgiven.

All you need, Tink!

In reply to Santee

“He could tell she was nervous as she entered the office. But when…”

Don’t need to know how he knows, just that he does.

Europ

In reply to Does swapping a SIM card work?

I’ve written in the past reports to support the Belgian judicial authorities in Belgium.

I don’t know how it’s implemented in the US but in in Europe both the IMSI (SIM card number) and the IMEI (Cell Phone unique ID) are stored in the radio network and even stored in the DWH to support judicial requests.

This means that any judicial department can request for for SIM or Cell phone swaps.
This can even be done in real time in Belgium, although I don’t know if real time is supported in all Europian countries.

The kind of reports I’ve written was for example:
– Who has called on sent an SMS who on which location
– Which SIM (IMSI) is used by which Mobile device (IMEI)
– Which Mobile device (IMEI)is used by which SIM (IMSI)
– Who called at a certain time in a certain location (antenna)
– etc.

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