7 ms·

What Your Cell Phone Can't Tell the Police

75 points by gbl08ma 12y ago

tantalor 12y ago
This reads like a textbook example of "circumstantial evidence".
- uxp 12y ago
  Evidence is only circumstantial if you can frequently prove that the evidence cannot stand alone. Sounds like common sense, but many facts throughout history have been debunked after new ways of looking at them challenged the common view. You would call me an idiot of I was adamant about the sun rotating around the Earth, but that wasn't always so. Similarly, triangulation has been used for a long time to pinpoint locations, but only now do we know that passive cellular triangulation is actually a singular approximation and so the idea that a deterministic location can be derived from the observation of transmissions is flawed.
- DrStalker 12y ago
  "Circumstantial evidence" is any evidence other than a direct eyewitness of the crime; if your fingerprints are at the crime scene, your shirt is covered in the victims blood, you're carrying a gun that matches the bullets pulled out of the victim and a busload of tourists filmed you leaving the victim's building after gunshots were heard that's all circumstantial. Those things all infer guilt, but don't directly prove it.
  - AnthonyMouse 12y ago
    > Those things all infer guilt, but don't directly prove it. Which is why they're all so untrustworthy. Take your example: If what actually happened is that you were sitting next to your friend having a beer when a madman came in and shot your friend, and then you wrestled the gun away from the madman and barely escaped with your life, you would get all that same "evidence."
    - stan_rogers 12y ago
      Given that there are only two kinds of evidence, circumstantial and eyewitness, and that eyewitness evidence is almost useless unless the witness knows the accused (and was close enough and had a good-enough look not to be mistaken) or the accused was apprehended in flagrante delicto, bet on circumstantial either way (to convict or to clear). Dismissing circumstantial evidence means that if you sort of resemble the impression that an eyewitness had of the perpetrator and were wearing clothes that were "brown, or maybe blue... it was kinda dark" and the testimony of that eyewitness just, you know, feels more credible than the seventeen people who will swear up and down that you were elsewhere at the time, then the more objective (but "merely circumstantial") evidence that can reliably place you elsewhere isn't going to be a whole lot of help to you.
      - AnthonyMouse 12y ago
        I'm not saying that eyewitness testimony is automatically better. It's generally pretty terrible, and people have all kinds of different incentives to lie on top of being mistaken. The underlying problem is that we're making decisions that change the course of lives based on weak evidence of any type. Nobody wants to actually follow "beyond a reasonable doubt" because it would mean too low a conviction rate, so instead we suffer too high a false conviction rate. But you're also confusing what classifies as one type of evidence or the other. The seventeen people who swear you were somewhere else are eyewitnesses to your alibi. In addition, circumstantial evidence is extremely useful to acquit, because although proof that you could have committed the crime doesn't prove that you did, proof that you could not have committed the crime does prove that you didn't. The prosecutor has a tough job, and they're supposed to, because they're proposing to lock a citizen in a cage for a number of years. That's a thing that should happen a lot less often than it does.
hello_there 12y ago
The article describes some circumstances under which a cell phone can be more precisely located. > Similarly, if you make an emergency 911 call, your company will use three towers to triangulate your location; if you’re using a smartphone, it will use G.P.S. to pinpoint where you are. If you’re the target of an ongoing investigation and law-enforcement agencies want to track you, they can ask a phone company to “ping” your phone in real time. The “ping” part caught my attention: this sounds like a method that actively queries the phone in a way that could be detected by the end user. Does anyone know if this is possible to detect? Would, for example, an Android phone allow a developer to write an app that could detect this and notify the user?
- aisenik 12y ago
  This is the sort of thing I'd expect them to implement in the black-box baseband processor. I doubt it'd be exposed to the host at all, though a little bit of sigint might do the trick.
- 13throwaway 12y ago
  I'm really interested in a less-trackable cell phone, but until I read this article, It didn't seem possible. I am really hoping a fully open source phone comes to the market soon. It wouldn't have this ping "feature", it could connect to the second or third closest tower, and it could completely shut off cell when on wifi.
  - gaius 12y ago
    Open source doesn't help, if you are using the hardware that has been certified to connect to the public network. It could have anything in it. You would need to start literally at the fab.
- dobbsbob 12y ago
  Phone baseband proprietary stack is bombarded with type0 SMS which will silently ack the msgs and thus 'ping' your location. There's probably carrier made tracking programs on SIMs too and/or your SIM can be modified by over the air update to install stealth tracking programs the host OS will never know about. FBI asked a carrier to do this once to track a fraud suspect http://www.wired.com/2013/04/verizon-rigmaiden-aircard/all/ http://www.wired.com/2013/04/verizon-rigmaiden-aircard/all/
giancarlostoro 12y ago
If all they have is location on a phone, that could also place other people in the area though. But I guess, that's irrelevant. There's also the chance that the murderer didn't carry their cell phone in the area whatsoever. I mean who goes and murders someone and talks on their phone at the same time anyway?
- spacehome 12y ago
  Lots of people, it turns out. Murder is a pretty irrational act to commit, so I wouldn't expect murderers to display tons of foresight in planning.
secabeen 12y ago
This is why I generally like having features like GPS and Google location tracking turned on. The police, government and large corporations already have access to lousy data they will happily use to my detriment. If I have better data, I can use it to my benefit.
- laggyluke 12y ago
  The problem is that you can spoof Google location tracking and other systems that actively report your location, but you can't (AFAIK) spoof your cellular tower data.
  - keyme 12y ago
    I don't know the level of difficulty involved in the former, but "spoofing" cell data is possible by making the phone connect to sub-optimal towers. This would cost you service quality and battery life, but you'd "appear" elsewhere. This requires reversing and patching proprietary software, though.
    - Tuna-Fish 12y ago
      The cell towers save the round trip time of each ping. This means that even if you connect to a far-away cell tower (which you can actually do just fine with a long metal cylinder and a kettle lid, no need to mess with software), they will be able to tell you were not near the tower in question.
      - robryk 12y ago
        Is the RTT really dominated by lightspeed delays and not processing in the phone?
        Tuna-Fish 12y ago
        The processing in the phone can be reliably removed from the equation using simple statistical methods.
stillsut 12y ago
Just like the inmate in Texas executed, and (wrongfully?) convicted on pseudo-science arson investigation evidence. I wonder what other type of crap is putting innocent people in jail? Maybe more interesting question: how can a jury of average citizens be expected to weigh this evidence when even FBI task forces can't completely figure it out?
- A_COMPUTER 12y ago
  >I wonder what other type of crap is putting innocent people in jail? Rhetorical question? It's polygraph, drug sniffing dogs and breathalyzer. There was a court case a while back about drug sniffing dogs that presented the empirically demonstrated fact that the dogs present false positives all the time; but the judges concluded that it resulted in so many convictions that it would be a disaster to prevent their being evidence in court (analogous to witch dunkings, I suppose.) And breathalyzers are electronic devices whose source code is not auditable because the it is a "trade secret." Convicted by breathalyzer result? Can't challenge the black box's findings.
  - dobbsbob 12y ago
    Police also use questionable blood splatter pattern 'science' they draw sweeping conclusions from
  - stephen_g 12y ago
    Do they convict based on a breathalyser reading alone in the US? I'm fairly sure that in my country/state, the breathalyser can only provide probable cause for them to do a blood test. Also, how could sniffer dogs provide evidence for court? Surely they couldn't convict without actually finding drugs?
    - judk 12y ago
      Dogs are used to (fraudulently) excuse otherwise-illegal searches, but otherwise evidence is same as otherwise.
- kevinpet 12y ago
hamiltonkibbe 12y ago
"A GPS transmitter" ... "Seize the GPS chip" an accurate description of technology is always nice

75 points by gbl08ma 12y ago

tantalor 12y ago

This reads like a textbook example of "circumstantial evidence".

uxp 12y ago
Evidence is only circumstantial if you can frequently prove that the evidence cannot stand alone. Sounds like common sense, but many facts throughout history have been debunked after new ways of looking at them challenged the common view. You would call me an idiot of I was adamant about the sun rotating around the Earth, but that wasn't always so. Similarly, triangulation has been used for a long time to pinpoint locations, but only now do we know that passive cellular triangulation is actually a singular approximation and so the idea that a deterministic location can be derived from the observation of transmissions is flawed.
DrStalker 12y ago
"Circumstantial evidence" is any evidence other than a direct eyewitness of the crime; if your fingerprints are at the crime scene, your shirt is covered in the victims blood, you're carrying a gun that matches the bullets pulled out of the victim and a busload of tourists filmed you leaving the victim's building after gunshots were heard that's all circumstantial. Those things all infer guilt, but don't directly prove it.
- AnthonyMouse 12y ago
  > Those things all infer guilt, but don't directly prove it. Which is why they're all so untrustworthy. Take your example: If what actually happened is that you were sitting next to your friend having a beer when a madman came in and shot your friend, and then you wrestled the gun away from the madman and barely escaped with your life, you would get all that same "evidence."
  - stan_rogers 12y ago
    Given that there are only two kinds of evidence, circumstantial and eyewitness, and that eyewitness evidence is almost useless unless the witness knows the accused (and was close enough and had a good-enough look not to be mistaken) or the accused was apprehended in flagrante delicto, bet on circumstantial either way (to convict or to clear). Dismissing circumstantial evidence means that if you sort of resemble the impression that an eyewitness had of the perpetrator and were wearing clothes that were "brown, or maybe blue... it was kinda dark" and the testimony of that eyewitness just, you know, feels more credible than the seventeen people who will swear up and down that you were elsewhere at the time, then the more objective (but "merely circumstantial") evidence that can reliably place you elsewhere isn't going to be a whole lot of help to you.
    - AnthonyMouse 12y ago
      I'm not saying that eyewitness testimony is automatically better. It's generally pretty terrible, and people have all kinds of different incentives to lie on top of being mistaken. The underlying problem is that we're making decisions that change the course of lives based on weak evidence of any type. Nobody wants to actually follow "beyond a reasonable doubt" because it would mean too low a conviction rate, so instead we suffer too high a false conviction rate. But you're also confusing what classifies as one type of evidence or the other. The seventeen people who swear you were somewhere else are eyewitnesses to your alibi. In addition, circumstantial evidence is extremely useful to acquit, because although proof that you could have committed the crime doesn't prove that you did, proof that you could not have committed the crime does prove that you didn't. The prosecutor has a tough job, and they're supposed to, because they're proposing to lock a citizen in a cage for a number of years. That's a thing that should happen a lot less often than it does.

hello_there 12y ago

The article describes some circumstances under which a cell phone can be more precisely located. > Similarly, if you make an emergency 911 call, your company will use three towers to triangulate your location; if you’re using a smartphone, it will use G.P.S. to pinpoint where you are. If you’re the target of an ongoing investigation and law-enforcement agencies want to track you, they can ask a phone company to “ping” your phone in real time. The “ping” part caught my attention: this sounds like a method that actively queries the phone in a way that could be detected by the end user. Does anyone know if this is possible to detect? Would, for example, an Android phone allow a developer to write an app that could detect this and notify the user?

aisenik 12y ago
This is the sort of thing I'd expect them to implement in the black-box baseband processor. I doubt it'd be exposed to the host at all, though a little bit of sigint might do the trick.
13throwaway 12y ago
I'm really interested in a less-trackable cell phone, but until I read this article, It didn't seem possible. I am really hoping a fully open source phone comes to the market soon. It wouldn't have this ping "feature", it could connect to the second or third closest tower, and it could completely shut off cell when on wifi.
- gaius 12y ago
  Open source doesn't help, if you are using the hardware that has been certified to connect to the public network. It could have anything in it. You would need to start literally at the fab.
dobbsbob 12y ago
Phone baseband proprietary stack is bombarded with type0 SMS which will silently ack the msgs and thus 'ping' your location. There's probably carrier made tracking programs on SIMs too and/or your SIM can be modified by over the air update to install stealth tracking programs the host OS will never know about. FBI asked a carrier to do this once to track a fraud suspect http://www.wired.com/2013/04/verizon-rigmaiden-aircard/all/ http://www.wired.com/2013/04/verizon-rigmaiden-aircard/all/

giancarlostoro 12y ago

If all they have is location on a phone, that could also place other people in the area though. But I guess, that's irrelevant. There's also the chance that the murderer didn't carry their cell phone in the area whatsoever. I mean who goes and murders someone and talks on their phone at the same time anyway?

spacehome 12y ago
Lots of people, it turns out. Murder is a pretty irrational act to commit, so I wouldn't expect murderers to display tons of foresight in planning.

secabeen 12y ago

This is why I generally like having features like GPS and Google location tracking turned on. The police, government and large corporations already have access to lousy data they will happily use to my detriment. If I have better data, I can use it to my benefit.

laggyluke 12y ago
The problem is that you can spoof Google location tracking and other systems that actively report your location, but you can't (AFAIK) spoof your cellular tower data.
- keyme 12y ago
  I don't know the level of difficulty involved in the former, but "spoofing" cell data is possible by making the phone connect to sub-optimal towers. This would cost you service quality and battery life, but you'd "appear" elsewhere. This requires reversing and patching proprietary software, though.
  - Tuna-Fish 12y ago
    The cell towers save the round trip time of each ping. This means that even if you connect to a far-away cell tower (which you can actually do just fine with a long metal cylinder and a kettle lid, no need to mess with software), they will be able to tell you were not near the tower in question.
    - robryk 12y ago
      Is the RTT really dominated by lightspeed delays and not processing in the phone?
      - Tuna-Fish 12y ago
        The processing in the phone can be reliably removed from the equation using simple statistical methods.

stillsut 12y ago

Just like the inmate in Texas executed, and (wrongfully?) convicted on pseudo-science arson investigation evidence. I wonder what other type of crap is putting innocent people in jail? Maybe more interesting question: how can a jury of average citizens be expected to weigh this evidence when even FBI task forces can't completely figure it out?

A_COMPUTER 12y ago
>I wonder what other type of crap is putting innocent people in jail? Rhetorical question? It's polygraph, drug sniffing dogs and breathalyzer. There was a court case a while back about drug sniffing dogs that presented the empirically demonstrated fact that the dogs present false positives all the time; but the judges concluded that it resulted in so many convictions that it would be a disaster to prevent their being evidence in court (analogous to witch dunkings, I suppose.) And breathalyzers are electronic devices whose source code is not auditable because the it is a "trade secret." Convicted by breathalyzer result? Can't challenge the black box's findings.
- dobbsbob 12y ago
  Police also use questionable blood splatter pattern 'science' they draw sweeping conclusions from
- stephen_g 12y ago
  Do they convict based on a breathalyser reading alone in the US? I'm fairly sure that in my country/state, the breathalyser can only provide probable cause for them to do a blood test. Also, how could sniffer dogs provide evidence for court? Surely they couldn't convict without actually finding drugs?
  - judk 12y ago
    Dogs are used to (fraudulently) excuse otherwise-illegal searches, but otherwise evidence is same as otherwise.
kevinpet 12y ago

hamiltonkibbe 12y ago

"A GPS transmitter" ... "Seize the GPS chip" an accurate description of technology is always nice