Tin foil

[Paupertas]

I'm just interested in why wrapping a phone in tin foil to evade it being detected is 'misguided' - I thought that this would work

The federal agents who arrested Ghislaine Maxwell found a cellphone wrapped in tin foil inside of her New Hampshire home in “a misguided effort to evade detection,” prosecutors said Monday.

https://www.nbcnews.com/news/us-news/gh ... n-n1233674

[Urbandreamer]

It might or might not prevent the PHONE being detected.

However I think that the argument being made is that it is her attempting to evade detection that was misguided.

Attempting to evade the authorities is a crime and wrapping the phone in foil may be seen as evidence that the crime was intended. Hence regardless of any other offence she has made herself liable to legal punishment, possibly including a jail sentence. Some might regard that as misguided.

[AleisterCrowley]

It would work if it formed an effective Faraday shield - no radio, no detection
With older phones the highly technical 'remove the battery' worked fine
I'm nervous about smartphones with soft power switches, they are always up to something even when 'off'

[eepee]

Stick it in a lidded tin can.

Regards,
ep

[swill453]

It would work if it formed an effective Faraday shield - no radio, no detection

But depending on contact etc. it might form an effective antenna!

Scott.

[neversay]

It would work if it formed an effective Faraday shield - no radio, no detection
With older phones the highly technical 'remove the battery' worked fine
I'm nervous about smartphones with soft power switches, they are always up to something even when 'off'

Good point. And the battery on mine (Samsung S10) is sealed-in.

[gryffron]

A Faraday cage must be earthed. Otherwise you are just making a large aerial.

A wrap of tinfoil would work, if properly earthed.

Putting it in a microwave works too. That's an effective Faraday cage. Just remember not to switch it on with the phone in there.

Gryff

[AleisterCrowley]

A Faraday cage must be earthed. Otherwise you are just making a large aerial.

..
Gryff

They work fine in aircraft.... (see also Faraday bags)

[servodude]

It would work if it formed an effective Faraday shield - no radio, no detection
With older phones the highly technical 'remove the battery' worked fine
I'm nervous about smartphones with soft power switches, they are always up to something even when 'off'

Good point. And the battery on mine (Samsung S10) is sealed-in.

Unless your real name is Andrew Windsor you've probably not got too much to worry about
- I bet he's sweating (if he can)

- sd

[stevensfo]

I'm just interested in why wrapping a phone in tin foil to evade it being detected is 'misguided' - I thought that this would work

The federal agents who arrested Ghislaine Maxwell found a cellphone wrapped in tin foil inside of her New Hampshire home in “a misguided effort to evade detection,” prosecutors said Monday.

https://www.nbcnews.com/news/us-news/gh ... n-n1233674

Leaving aside the person herself, I can't ever see it becoming illegal to stop a phone from being detected. The legal precedent is too terrifying! Lots of people are already paranoid enough about what info is transmitted about them. Some bank apps require access to location data.
But with smartphones getting cheaper, it's easy enough to get spares to use when travelling and sim cards are ten a penny.
Must go and buy more aluminium foil.

Steve

[bungeejumper]

Some years ago, I worked with a top specialist in the security sector who explained to me how very difficult it was to make a mobile phone totally undetectable. Drug dealers, terrorists and other bad people tended to rely on the notion that if you removed both the battery and the sim card from your phone - or simply swapped the sim - then that would make you instantly untraceable. But as many of them were to discover to their cost, it was not always so.

Well, that's what he said anyway. Something about how each phone handset has a unique identity, sort of like an RFID tag that can be read from a distance if you used the right scanner. It was all well above my non-techie pay grade. Ring any bells?

BJ

[didds]

Well, that's what he said anyway. Something about how each phone handset has a unique identity, sort of like an RFID tag that can be read from a distance if you used the right scanner. It was all well above my non-techie pay grade. Ring any bells?

BJ

Im struggling to think how a phone without a battery could actually "transmit" its unique ID (IMEI presumably)? More than happy to be better educated

didds

[AleisterCrowley]

Sounds a bit unlikely ! - and yes it would be the IMEI

[gryffron]

Modern smartphones definitely have a unique ID programmed in as an anti theft device. So swapping SIMs doesn't hide the phone. But like the previous posters, I cannot imagine how they could communicate this without a battery. It takes a reasonable amount of power to communicate with a mobile mast. So the tiny batteries sometimes used to preserve memory wouldn't last more than a smidge when transmitting. Not sure if cheapy disposables have the same feature? But I doubt it.

if you used the right scanner

Scanner won't help, they swap between frequencies and base stations very frequently. Modern phones don't have an analogue tuned circuit. Mobile phone aerials just collect random radio noise and use digital number crunching to calculate the bits of signal they want. So an old style TV-detector van would be useless.

You can spoof a mobile by providing the only available base station and shutting off all the others nearby. So it HAS to route its calls via the station you are monitoring. This may be done for hostage/terrorist situations, but unlikely to be practical for everyday criminality.

Anyway, they can track phones down to an exact flat number in a block of flats. It must be true, I saw it in "Line of Duty".

Gryff

[AleisterCrowley]

The network has to know approximately where mobiles are for paging purposes. If someone calls your mobile the network can't page every cell, so cells are grouped into clusters (location areas/LACs)
If you move from one to another the phone will do a location update (basically 'page me in this group of cells now, not the one I just left') At this point there is a two way connection so the network knows exactly which cell the mobile is on. Mobiles also do a Periodic Location Update if they have been idle for a while - the exact time period is set by the network (T3212 -Periodic Location Update Timer )
Obviously it doesn't do this if it has no battery...
There are ways to force a phone into a two way connection, but sadly I've run out of space so can't elucidate

[AF62]

You can spoof a mobile by providing the only available base station and shutting off all the others nearby. So it HAS to route its calls via the station you are monitoring. This may be done for hostage/terrorist situations, but unlikely to be practical for everyday criminality.

That used to be the case, now just get a Stingray - https://en.wikipedia.org/wiki/Stingray_phone_tracker

[UncleEbenezer]

Well, that's what he said anyway. Something about how each phone handset has a unique identity, sort of like an RFID tag that can be read from a distance if you used the right scanner. It was all well above my non-techie pay grade. Ring any bells?

BJ

Every network device has its unique hardware identity. It's one of the security settings available on many wifi routers: only allow known devices, and identify each allowed device to it.

But it's not a cryptographic signature, so it's not secure against a serious attacker. Nor perhaps against a corner-cutting manufacturer of cheap-and-nasty kit.

That may or may not be what your former colleague was talking about.

[gryffron]

Every network device has its unique hardware identity.

Yes. But in the case of cheap tacky disposable mobiles, is this ID in the phone or the SIM? I suspect the latter. Can't see any reason to put one in the former, since it can't work on its own.

Gryff

[servodude]

Every network device has its unique hardware identity.

Yes. But in the case of cheap tacky disposable mobiles, is this ID in the phone or the SIM? I suspect the latter. Can't see any reason to put one in the former, since it can't work on its own.

Gryff

Given this is DAK here's some stuff I K:

The SIM, if it exists, is logically identified by the IMSI number (Subscriber Identifier); this is basically "who gets billed and what for"

The SIM card (or eSIM) if it exists is identified by its ICCID (Integrated Circuit Card Identifier); it is possible to change the IMSI on a SIM but not it's ICCID. This is not done often on "cards" but is quite common for devices using eSIM (which are onboard chips that do the job of a SIM card)

The mobile phone/device is identified by the IMEI (Equipment Identity) all of them have one; even if cheap and/or tacky.
If it doesn't have a SIM or eSIM (e.g. on a CDMA network) it will use an MEID which is the IMEI without the checksum digit on the end

Everything sending data will have a MAC address (Media Access Control) and this is what you normally allow/ban on your router to prevent people using it who might have your password. These are assumed to be unique for the purposes of the network routing - but in practice they are trivial to change or misrepresent: if you've got WPS enabled on your router and I've tried to use it to find the password, I'll know the MAC address of everything connected.

The network will know what a device reports for all of the relevant identifiers above

Have fun
- sd

[AF62]

Everything sending data will have a MAC address (Media Access Control) and this is what you normally allow/ban on your router to prevent people using it who might have your password. These are assumed to be unique for the purposes of the network routing - but in practice they are trivial to change or misrepresent: if you've got WPS enabled on your router and I've tried to use it to find the password, I'll know the MAC address of everything connected.

The network will know what a device reports for all of the relevant identifiers above

IOS 14 (due out shortly) randomises the MAC address automatically so that will mean those using Apple devices won’t be able to be tracked with this method.

https://support.apple.com/en-us/HT211227

Although as the support article points out, constantly changing MAC may cause issues. However since Apple has such dominance then any equipment which doesn’t work with this system will undoubtedly have to be changed to something that does work with Apple.