[HN Gopher] SeaGlass: City-Wide IMSI-Catcher Detection (2017)
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       SeaGlass: City-Wide IMSI-Catcher Detection (2017)
        
       Author : kogir
       Score  : 281 points
       Date   : 2021-05-16 13:53 UTC (9 hours ago)
        
 (HTM) web link (seaglass.cs.washington.edu)
 (TXT) w3m dump (seaglass.cs.washington.edu)
        
       | nceqs3 wrote:
       | https://news.ycombinator.com/item?id=14474956
        
       | DyslexicAtheist wrote:
       | The German government has just published a paper on the
       | requirement for telecom operators to ensure LEA continue to be
       | able to _covertly_ intercept traffic in 5G: "Ensuring Undetected
       | use of the IMSI Catcher", the paper which is in German
       | (https://posteo.de/FormulierungshilfeBMI.pdf) reads:
       | 
       |  _" > Mobile network operators must ensure security authorities
       | can use IMSI Catchers without the end user becoming aware of
       | this. According to the TKG-E, mobile operators must continue to
       | allow IMSI catchers in accordance with statutory investigative
       | measures. Until now, it's unnecessary for operators to act so
       | that members of the Security authorities can use IMSI-Catchers,
       | as they "simply" pretend to be a base station. In new mobile
       | networks, devices brought into the network must be actively
       | "accepted" by the network and otherwise cannot be used. As a
       | result, it will no longer be possible to insert IMSI catchers of
       | "previous design" into the new networks. We acknowledge that in
       | the future unauthorised persons, such as foreign intelligence
       | services can no longer use them. At the same time, it will no
       | longer be possible for German security authorities to use an IMSI
       | catcher without the cooperation of the mobile operator. The
       | necessary regulations for the participation of the mobile
       | operator are already included in the draft TKG, but the necessary
       | addition is missing that the introduction of an IMSI catcher by
       | security authorities may not be known to the end user."_
       | 
       | Most people will think this is a fringe scenario which will never
       | affect them. But they are very common in international airports:
       | 
       |  _> At Trudeau airport, Radio-Canada detected the catcher 's
       | presence through the use of a CryptoPhone -- a cellphone look-
       | alike that emits red alerts when a fake antenna tries to catch
       | its signal. Several red alerts were received, throughout the
       | afternoon and early evening, in the section of the airport for
       | U.S. departures._
       | 
       | https://www.cbc.ca/news/canada/montreal/trudeau-airport-spyi...
       | 
       |  _> For two months last year, researchers at the University of
       | Washington paid drivers of an unidentified ridesharing service to
       | keep custom-made sensors in the trunks of their cars, converting
       | those vehicles into mobile cellular data collectors. They used
       | the results to map out practically every cell tower in the cities
       | of Seattle and Milwaukee--along with at least two anomalous
       | transmitters they believe were likely stingrays, located at the
       | Seattle office of the US Customs and Immigration Service, and the
       | Seattle-Tacoma Airport._
       | 
       | https://www.wired.com/2017/06/researchers-use-rideshares-sni...
       | 
       |  _> The devices are operated out of at least five U.S. airports,
       | "covering most of the U.S. population". It is unclear whether the
       | U.S. Marshals Service requests court orders to use the devices._
       | 
       | source: https://en.wikipedia.org/wiki/Dirtbox_(cell_phone)
       | 
       | For a "modern" take on this subject (info relevant to 3G is
       | outdated unless they do a downgrade attack on you first), see
       | this article and the linked videos that go into the issues LEO
       | face with 4G/5G and the "crocodile hunter" software that is an
       | EFF project to identify them: https://www.pcmag.com/news/police-
       | spying-on-your-phone-ask-c...
        
       | [deleted]
        
       | baybal2 wrote:
       | There used to be a very handy Android app, now booted off the
       | Google Market, called "GSM Spy Finder" which worked on MediaTek
       | SoCs.
       | 
       | https://apkplz.net/app/kz.galan.antispy
        
         | joering2 wrote:
         | I cannot find anything on it - does anyone know the reason it
         | was booted out by Google?
        
           | heavyset_go wrote:
           | Google will boot things that use APIs that they don't want
           | app developers using, or apps that "abuse" the APIs they are
           | allowed to use.
        
         | anonymousiam wrote:
         | There is still this one:
         | https://play.google.com/store/apps/details?id=com.wilysis.ce...
         | (Network Cell Info).
         | 
         | It will reveal a catcher nearby if you are already familiar
         | with the local area.
        
         | sigg3 wrote:
         | You can also use SnoopSnitch from F-droid for this.
         | 
         | https://f-droid.org/packages/de.srlabs.snoopsnitch
        
           | hnjst wrote:
           | There was another one in f-droid (or at least it was named
           | differently at the time) that I had installed and running by
           | curiosity a few years ago. I more or less forgot it until one
           | day while I was driving on the highway and got forcibly
           | directed out because of a blockade set by protesters (nation-
           | wide protests by farmers occurring at that time). Once in the
           | vicinity of said blockade I got notified unequivocally that
           | something weird was happening to the cellular network. I
           | guess law enforcement people were using IMSI catchers to
           | monitor protesters.
           | 
           | Just anecdotal evidence, however, while I almost never got
           | false positive alerts from this app (once at the arrival of
           | an international flight), the one time it triggered a
           | notification, it was in a highly probable situation.
           | 
           | Communication between our devices and these base stations
           | being so opaque (closed-source baseband processors/OS not
           | helping there) and sensible, I'm glad these projects exist
           | and I just installed this one, blaming myself for not doing
           | so earlier.
        
           | DyslexicAtheist wrote:
           | since some years already any app based solutions are useless
           | in practice since they yield a huge amount of false positives
           | or no results at all. The talk on crocodile hunter (an EFF
           | software) goes into why that is so:
           | https://www.pcmag.com/news/police-spying-on-your-phone-
           | ask-c...
           | 
           | edit: if you've ever spent some time sitting on a plane (non
           | domestic) and your phone was on during the time-window when
           | boarding is ongoing and just before the aircraft taxis to the
           | runway, then there is a very good chance that you've
           | connected to one of these before. It's a way to match known
           | cell numbers of individuals where an arrest warrant has been
           | issued (or otherwise individuals that are monitored) against
           | actual passengers phones (who might be traveling with a fake
           | ID). If somebody on your flight was ever lifted off the plane
           | by LEA (but obviously has made it through security into the
           | plane) they are very likely the target of such a dirtbox
           | intercept.
        
             | gruez wrote:
             | >If somebody on your flight was ever lifted off the plane
             | by LEA (but obviously has made it through security into the
             | plane) they are very likely the target of such a dirtbox
             | intercept.
             | 
             | You'd think fugatives won't bring their phones with them,
             | turn them off unless absolutely necessary, or use burners.
        
               | DyslexicAtheist wrote:
               | yeah one would think so!
               | 
               | in reality huge number of arrests are made due to
               | incredibly dumb mistakes (and not because LEO's used some
               | super newsworthy hack).
        
       | [deleted]
        
       | lykr0n wrote:
       | Ooh. New project for today. Deploy this locally and figure out
       | how to make this a public service where people can run their
       | devices and the data is uploaded to a central database in real-
       | ish time so people can see suspect changes.
       | 
       | EDIT: This should have a 2017 tag, as the code is 4 years old and
       | I assume the same is true for the website.
        
       | dweekly wrote:
       | Now we just need a few of these on coordinating drones to
       | triangulate in real-time and snap some pictures of the
       | transmission source.
        
         | jhart99 wrote:
         | You could do it with a couple of KerberosSDR units.
        
       | ChrisMarshallNY wrote:
       | This is cool!
       | 
       | Of course, it will only be a matter of time before the stingray-
       | users figure out how to fool them...
        
         | sschueller wrote:
         | Maybe we get enough time to finally make it illegal to use one.
         | If this isn't mass surveillance then what is?
        
           | ng55QPSK wrote:
           | "a matter of national security" - there are endless
           | interfaces into the network (by law) for lawful interception
           | and some of them are designed in such a way that Interceptor
           | E1 cannot see what Interceptor E2 is trying to read.
           | 
           | Still, some 'other' interested parties that have reasons not
           | to use the standardised interfaces.
           | 
           | For 5G at lot of additional security measures CAN be enabled,
           | but you can guess who started to complain about that.
        
         | xfitm3 wrote:
         | I fear the same. This research will drive stingray to be more
         | stealth.
        
           | hilbert42 wrote:
           | Right, that is highly probable and the fact that it's likely
           | to happen will drive nefarious operators to illegally change
           | IMSI numbers,etc., that is, if it's not already happening on
           | a grand scale. This could lead to a technology war between
           | law enforcement and crooks where the main victims will be
           | innocent people.
           | 
           | The bigger and more important issues are that (a) our police
           | forces are becoming more militaristic and are acting more
           | like invading armies without themselves conforming to the law
           | not to mention the fact that they are also acting
           | underhandedly and by stealth (which leads the citizenry to
           | distrust them), and (b) the issue of citizens' right to
           | privacy has not been properly or adequately addressed by
           | legislators.
           | 
           | The fact that our governments have precious little control
           | over their various agencies is also of great concern.
        
         | hn_throwaway_99 wrote:
         | Seems like that would maybe be a game of cat-and-mouse, but
         | fundamentally these IMSI catchers _have_ to have an
         | identifiable signature. That is, in order to work they need to
         | mimic an existing cell tower as much as possible, but it is
         | exactly because of that mimicry that they can be detected over
         | time (e.g. because the signal is coming from a different
         | location).
        
           | coretx wrote:
           | Using more than one antenna will expose a phase difference
           | and drifting in time can't be avoided either unless they
           | waste millions of tax money on ultra expensive TCXO's.
           | Herefore I suspect that they'll passively identify a signal
           | and order the service provider to decrypt it at their
           | backbone. If France/the GSM foundation could pull of that
           | encryption is to be downgraded in strategic countries; surely
           | some other powerhungry nationstate will beat that record.
        
       | wcarss wrote:
       | In case anyone else is wondering what an IMSI-Catcher is, let me
       | save you a google:
       | 
       | "An international mobile subscriber identity-catcher, or IMSI-
       | catcher, is a telephone eavesdropping device used for
       | intercepting mobile phone traffic and tracking location data of
       | mobile phone users."
       | 
       | 1 - https://en.wikipedia.org/wiki/IMSI-catcher
        
         | Imagenuity wrote:
         | The Stingray is a commercially available model that you may
         | have heard of.
        
         | heavyset_go wrote:
         | They're also cheap, easy to use and deployed all over the
         | country by local law enforcement. It isn't just three letter
         | agencies using them, it's your local police department, too. No
         | warrants needed, either.
        
       | mnw21cam wrote:
       | Is it just me that looks at the equipment photo, and thinks -
       | you're using an inverter to convert 12VDC to 120VAC, then a
       | couple of wall plug transformers to convert that back down to
       | low-voltage DC - why don't you just use a DC regulator?
        
         | bombcar wrote:
         | Everything is off-the-shelf: you can find 12DC to 120AC at
         | Walmart, but a DC/DC regulator is harder to find and more
         | difficult to configure and setup correctly.
        
         | sjruckle wrote:
         | Car 12v systems can be really noisy. The inverter and power
         | bricks are pretty much guaranteed to filter all that out.
         | 
         | Besides that, this way doesn't need any soldering, which is
         | nice.
        
           | op00to wrote:
           | Inverters and power bricks are noisy too.
        
           | tzs wrote:
           | > Car 12v systems can be really noisy.
           | 
           | A 12 V lead acid battery ranges from around 12.7 volts when
           | fully charged down to around 12.2 at 50% (the minimum
           | recommended charge level for typical car batteries). When
           | starting the car, the voltage will drop below that. When the
           | alternator is running to charge the battery it is around 14
           | V.
           | 
           | Is there any regulation or filtering on the 12 V ports on
           | cars, or do devices plugged into them see it all--the
           | alternator voltage when it is running, a big drop when
           | starting, and 12.7-12.7 at other times?
        
             | anyfoo wrote:
             | Not necessarily, and there is way worse stuff on that power
             | source than that. For example, you have to guard against
             | things like "load dump" where voltage can spike up to
             | rather high voltages momentarily (80V or so, don't know the
             | actual spec right now).
             | 
             | Chances are that a modern car has more regulation and
             | protection between battery/alternator and the 12V plug, but
             | you don't usually know what, and the spec doesn't (or at
             | least didn't when i looked into it) require it.
        
             | JoshTriplett wrote:
             | There's no standardized regulation or filtering; devices
             | typically see it all. And it's much more than the
             | alternator voltage; a device might see transient 24V or
             | more, and as little as 9V.
             | 
             | See https://en.wikipedia.org/wiki/Automobile_auxiliary_powe
             | r_out... for more.
             | 
             | Modern chargers tend to be really forgiving, and they're
             | often powering a device that has its own battery, so there
             | are multiple levels of regulation between the car and the
             | device.
             | 
             | On the other hand, I've used automotive adapters that do a
             | simple DC-DC conversion with no regulation, and pass
             | through to a barrel connector to a device that would
             | otherwise be powered by standard alkaline disposable
             | batteries. Those aren't nearly as robust, and I've seen
             | devices fail or power-cycle due to undervolting.
        
             | detaro wrote:
             | No filtering, it goes directly to the general power rails
             | in the car, with all the noise included. Devices are
             | responsible for filtering/protection as needed.
        
       | jdc wrote:
       | BOM from the paper:
       | 
       | Telit GT-864 QUAD/PY GSM modem $65
       | 
       | External antenna $25
       | 
       | Raspberry Pi 2B+2 $35
       | 
       | GPS (GlobalSat BU-353) $30
       | 
       | Bait Phone (Motorola Moto-G 4G LTE) $95
       | 
       | 4G Hotspot (ZTE Z917) + 3 month plan $100
       | 
       | DC/AC inverter $26
       | 
       | Powered USB Hub $17
       | 
       | Pi accessories $15
       | 
       | SD Card (32 GB) $17
       | 
       | Modem accessories $30
       | 
       | Cables $35
       | 
       | Box $12
       | 
       | Total $502
       | 
       | https://seaglass-web.s3.amazonaws.com/SeaGlass___PETS_2017.p...
        
         | jcrawfordor wrote:
         | While the project has largely languished lately, I
         | reimplemented a sensor with similar capabilities to Project
         | Seaglass with the goal of a lower BOM cost and easier purchase
         | - the particular Telit module they used is discontinued and
         | hard to obtain. My BOM is around $160 and could be lowered. See
         | here: https://github.com/jcrawfordor/cellscan
        
       | 4gotunameagain wrote:
       | Partnering with rideshare drivers to maximize coverage of the
       | mobile units is quite clever.
       | 
       | Glad things like these are being done
        
       | nceqs3 wrote:
       | Is this open source? Would love to run it in DC. Would imagine
       | quite a few hits.
        
         | LargoLasskhyfv wrote:
         | https://github.com/seaglass-project/seaglass
        
         | baybal2 wrote:
         | > Would love to run it in DC.
         | 
         | You will probably find a lot, but mostly from SMS spammers
         | 
         | https://m.alibaba.com/product/1600220614935/detail.html
         | 
         | IMSI catchers are pretty much freely available for everybody to
         | use, and now closing on becoming tiny, and portable:
         | https://m.alibaba.com/product/1600226966011/detail.html
         | 
         | P.S. The company has quite an interesting list of buyers:
         | https://www.exporthub.com/shenzhen-thinkwell-digital-co-ltd-...
         | . Including one "eternal friend" of US who has recently been
         | caught red handed stingraying the state department, and the
         | whitehouse.
        
           | nanna wrote:
           | > P.S. The company has quite an interesting list of buyers:
           | https://www.exporthub.com/shenzhen-thinkwell-digital-co-
           | ltd-... . Including one "eternal friend" of US who has
           | recently been caught red handed stingraying the state
           | department, and the whitehouse.
           | 
           | Link is to a motorcycle mp3 player. What am I missing?
        
             | baybal2 wrote:
             | Looks like an SEO spam then
        
           | 2Gkashmiri wrote:
           | What... is the price of these again ? Im on mobile and the
           | price in my currency shows this specific one in upwards of us
           | $ 18k+? Is it that expensive or is alibaba somehow showing me
           | wrong price
        
             | InvaderFizz wrote:
             | Not a wrong price, $18k USD is downright cheap for what it
             | does for the intended customer base.
        
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