X-Git-Url: https://pere.pagekite.me/gitweb/homepage.git/blobdiff_plain/5ba84b59a210eafc0a4f9923d81fabdf1715ceac..cb2bffc9f0c093d20f059990477781700cd1f6a8:/blog/archive/2017/09/09.rss

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                 <link>http://people.skolelinux.org/pere/blog/</link>
 
 	
+	<item>
+		<title>Easier recipe to observe the cell phones around you</title>
+		<link>http://people.skolelinux.org/pere/blog/Easier_recipe_to_observe_the_cell_phones_around_you.html</link>        
+		<guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Easier_recipe_to_observe_the_cell_phones_around_you.html</guid>
+                <pubDate>Sun, 24 Sep 2017 08:30:00 +0200</pubDate>
+		<description>&lt;p&gt;A little more than a month ago I wrote
+&lt;a href=&quot;http://people.skolelinux.org/pere/blog/Simpler_recipe_on_how_to_make_a_simple__7_IMSI_Catcher_using_Debian.html&quot;&gt;how
+to observe the SIM card ID (aka IMSI number) of mobile phones talking
+to nearby mobile phone base stations using Debian GNU/Linux and a
+cheap USB software defined radio&lt;/a&gt;, and thus being able to pinpoint
+the location of people and equipment (like cars and trains) with an
+accuracy of a few kilometer.  Since then we have worked to make the
+procedure even simpler, and it is now possible to do this without any
+manual frequency tuning and without building your own packages.&lt;/p&gt;
+
+&lt;p&gt;The &lt;a href=&quot;https://tracker.debian.org/pkg/gr-gsm&quot;&gt;gr-gsm&lt;/a&gt;
+package is now included in Debian testing and unstable, and the
+IMSI-catcher code no longer require root access to fetch and decode
+the GSM data collected using gr-gsm.&lt;/p&gt;
+
+&lt;p&gt;Here is an updated recipe, using packages built by Debian and a git
+clone of two python scripts:&lt;/p&gt;
+
+&lt;ol&gt;
+
+&lt;li&gt;Start with a Debian machine running the Buster version (aka
+  testing).&lt;/li&gt;
+
+&lt;li&gt;Run &#39;&lt;tt&gt;apt install gr-gsm python-numpy python-scipy
+  python-scapy&lt;/tt&gt;&#39; as root to install required packages.&lt;/li&gt;
+
+&lt;li&gt;Fetch the code decoding GSM packages using &#39;&lt;tt&gt;git clone
+  github.com/Oros42/IMSI-catcher.git&lt;/tt&gt;&#39;.&lt;/li&gt;
+
+&lt;li&gt;Insert USB software defined radio supported by GNU Radio.&lt;/li&gt;
+
+&lt;li&gt;Enter the IMSI-catcher directory and run &#39;&lt;tt&gt;python
+  scan-and-livemon&lt;/tt&gt;&#39; to locate the frequency of nearby base
+  stations and start listening for GSM packages on one of them.&lt;/li&gt;
+
+&lt;li&gt;Enter the IMSI-catcher directory and run &#39;&lt;tt&gt;python
+  simple_IMSI-catcher.py&lt;/tt&gt;&#39; to display the collected information.&lt;/li&gt;
+
+&lt;/ol&gt;
+
+&lt;p&gt;Note, due to a bug somewhere the scan-and-livemon program (actually
+&lt;a href=&quot;https://github.com/ptrkrysik/gr-gsm/issues/336&quot;&gt;its underlying
+program grgsm_scanner&lt;/a&gt;) do not work with the HackRF radio.  It do
+work with RTL 8232 and other similar USB radio receivers you can get
+very cheaply
+(&lt;a href=&quot;https://www.ebay.com/sch/items/?_nkw=rtl+2832&quot;&gt;for example
+from ebay&lt;/a&gt;), so for now the solution is to scan using the RTL radio
+and only use HackRF for fetching GSM data.&lt;/p&gt;
+
+&lt;p&gt;As far as I can tell, a cell phone only show up on one of the
+frequencies at the time, so if you are going to track and count every
+cell phone around you, you need to listen to all the frequencies used.
+To listen to several frequencies, use the --numrecv argument to
+scan-and-livemon to use several receivers.  Further, I am not sure if
+phones using 3G or 4G will show as talking GSM to base stations, so
+this approach might not see all phones around you.  I typically see
+0-400 IMSI numbers an hour when looking around where I live.&lt;/p&gt;
+
+&lt;p&gt;I&#39;ve tried to run the scanner on a
+&lt;a href=&quot;https://wiki.debian.org/RaspberryPi&quot;&gt;Raspberry Pi 2 and 3
+running Debian Buster&lt;/a&gt;, but the grgsm_livemon_headless process seem
+to be too CPU intensive to keep up.  When GNU Radio print &#39;O&#39; to
+stdout, I am told there it is caused by a buffer overflow between the
+radio and GNU Radio, caused by the program being unable to read the
+GSM data fast enough.  If you see a stream of &#39;O&#39;s from the terminal
+where you started scan-and-livemon, you need a give the process more
+CPU power.  Perhaps someone are able to optimize the code to a point
+where it become possible to set up RPi3 based GSM sniffers?  I tried
+using Raspbian instead of Debian, but there seem to be something wrong
+with GNU Radio on raspbian, causing glibc to abort().&lt;/p&gt;
+</description>
+	</item>
+	
 	<item>
 		<title>Datalagringsdirektivet kaster skygger over Høyre og Arbeiderpartiet</title>
 		<link>http://people.skolelinux.org/pere/blog/Datalagringsdirektivet_kaster_skygger_over_H_yre_og_Arbeiderpartiet.html</link>