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diff --git a/2011/gsm-ensa2011/NevadaTestSite.jpg b/2011/gsm-ensa2011/NevadaTestSite.jpg Binary files differnew file mode 100644 index 0000000..aa3a627 --- /dev/null +++ b/2011/gsm-ensa2011/NevadaTestSite.jpg diff --git a/2011/gsm-ensa2011/OBTSBM2010.jpg b/2011/gsm-ensa2011/OBTSBM2010.jpg Binary files differnew file mode 100644 index 0000000..7759978 --- /dev/null +++ b/2011/gsm-ensa2011/OBTSBM2010.jpg diff --git a/2011/gsm-ensa2011/abstract.txt b/2011/gsm-ensa2011/abstract.txt new file mode 100644 index 0000000..2a3542c --- /dev/null +++ b/2011/gsm-ensa2011/abstract.txt @@ -0,0 +1,26 @@ +Free Software for GSM networks + +During its 25 year history, Free Software has ventured in many areas of +computing, such as TCP/IP networks, Internet servers, personal computers, +laptops, desktop computers, embedded devices, and so on. + +However, there are other areas of computing that - until very recently - have +not yet seen any Free Software. One prime example is cellular telephony +networks. More than 3 billion subscribers use GSM cellular phones around the +world. All components in the public GSM networks are proprietary +both on the network side and on the telephon side. + +The cellular networks consist of components like base stations, telephone +switches, all running proprietary software. + +The cellular phones - even those running Free Software based operating systems +liek Android - have a separate computer called "baseband processor" that +interacts with the GSM network and runs proprietary software. + +Since 2009, projects like OpenBTS, OpenBSC and OsmocomBB have been created to +change this. They all implement components of a GSM network as Free Software. + +Harald Welte is the founder of OpenBSC and OsmocomBB. He will discuss the +proprietary nature of the GSM world, the progress of Free Software in GSM +and how the GSM related Free Software projects can be used in research +and production. diff --git a/2011/gsm-ensa2011/bts_tree_full.jpg b/2011/gsm-ensa2011/bts_tree_full.jpg Binary files differnew file mode 100644 index 0000000..6b5c5e8 --- /dev/null +++ b/2011/gsm-ensa2011/bts_tree_full.jpg diff --git a/2011/gsm-ensa2011/c123_pcb.jpg b/2011/gsm-ensa2011/c123_pcb.jpg Binary files differnew file mode 100644 index 0000000..a9f24fc --- /dev/null +++ b/2011/gsm-ensa2011/c123_pcb.jpg diff --git a/2011/gsm-ensa2011/calypso-block.pdf b/2011/gsm-ensa2011/calypso-block.pdf Binary files differnew file mode 100644 index 0000000..27f8be8 --- /dev/null +++ b/2011/gsm-ensa2011/calypso-block.pdf diff --git a/2011/gsm-ensa2011/gsm.pdf b/2011/gsm-ensa2011/gsm.pdf Binary files differnew file mode 100644 index 0000000..bb403ee --- /dev/null +++ b/2011/gsm-ensa2011/gsm.pdf diff --git a/2011/gsm-ensa2011/gsm.snm b/2011/gsm-ensa2011/gsm.snm new file mode 100644 index 0000000..e69de29 --- /dev/null +++ b/2011/gsm-ensa2011/gsm.snm diff --git a/2011/gsm-ensa2011/gsm.tex b/2011/gsm-ensa2011/gsm.tex new file mode 100644 index 0000000..746611f --- /dev/null +++ b/2011/gsm-ensa2011/gsm.tex @@ -0,0 +1,305 @@ +% $Header: /cvsroot/latex-beamer/latex-beamer/solutions/conference-talks/conference-ornate-20min.en.tex,v 1.7 2007/01/28 20:48:23 tantau Exp $ + +\documentclass{beamer} + +\usepackage{url} +\makeatletter +\def\url@leostyle{% + \@ifundefined{selectfont}{\def\UrlFont{\sf}}{\def\UrlFont{\tiny\ttfamily}}} +\makeatother +%% Now actually use the newly defined style. +\urlstyle{leo} + + +% This file is a solution template for: + +% - Talk at a conference/colloquium. +% - Talk length is about 20min. +% - Style is ornate. + + + +% Copyright 2004 by Till Tantau <tantau@users.sourceforge.net>. +% +% In principle, this file can be redistributed and/or modified under +% the terms of the GNU Public License, version 2. +% +% However, this file is supposed to be a template to be modified +% for your own needs. For this reason, if you use this file as a +% template and not specifically distribute it as part of a another +% package/program, I grant the extra permission to freely copy and +% modify this file as you see fit and even to delete this copyright +% notice. + + +\mode<presentation> +{ + \usetheme{Warsaw} + % or ... + + \setbeamercovered{transparent} + % or whatever (possibly just delete it) +} + + +\usepackage[english]{babel} +% or whatever + +\usepackage[latin1]{inputenc} +% or whatever + +\usepackage{times} +\usepackage[T1]{fontenc} +\usepackage{subfigure} +\usepackage{hyperref} +% Or whatever. Note that the encoding and the font should match. If T1 +% does not look nice, try deleting the line with the fontenc. + + +\title{Free Software for GSM cellular telephony} + +\subtitle +{OpenBSC, OsmoSGSN, OpenGGSN, OsmocomBB} + +\author{Harald Welte} + +\institute +{gnumonks.org\\gpl-violations.org\\osmocom.org\\airprobe.org\\hmw-consulting.de} +% - Use the \inst command only if there are several affiliations. +% - Keep it simple, no one is interested in your street address. + +\date[ENSA 2011] % (optional, should be abbreviation of conference name) +{ENSA, May 2011, Tetouan/Morocco} +% - Either use conference name or its abbreviation. +% - Not really informative to the audience, more for people (including +% yourself) who are reading the slides online + +\subject{GSM Security} +% This is only inserted into the PDF information catalog. Can be left +% out. + + + +% If you have a file called "university-logo-filename.xxx", where xxx +% is a graphic format that can be processed by latex or pdflatex, +% resp., then you can add a logo as follows: + +% \pgfdeclareimage[height=0.5cm]{university-logo}{university-logo-filename} +% \logo{\pgfuseimage{university-logo}} + + + +% Delete this, if you do not want the table of contents to pop up at +% the beginning of each subsection: +%\AtBeginSubsection[] +%{ +% \begin{frame}<beamer>{Outline} +% \tableofcontents[currentsection,currentsubsection] +% \end{frame} +%} + + +% If you wish to uncover everything in a step-wise fashion, uncomment +% the following command: + +%\beamerdefaultoverlayspecification{<+->} + + +\begin{document} + +\begin{frame} + \titlepage +\end{frame} + +\begin{frame}{Outline} + \tableofcontents[hideallsubsections] + % You might wish to add the option [pausesections] +\end{frame} + + +% Structuring a talk is a difficult task and the following structure +% may not be suitable. Here are some rules that apply for this +% solution: + +% - Exactly two or three sections (other than the summary). +% - At *most* three subsections per section. +% - Talk about 30s to 2min per frame. So there should be between about +% 15 and 30 frames, all told. + +% - A conference audience is likely to know very little of what you +% are going to talk about. So *simplify*! +% - In a 20min talk, getting the main ideas across is hard +% enough. Leave out details, even if it means being less precise than +% you think necessary. +% - If you omit details that are vital to the proof/implementation, +% just say so once. Everybody will be happy with that. + +\begin{frame}{About the speaker} +\begin{itemize} + \item Using + playing with GNU/Linux since 1994 + \item Kernel / bootloader / driver / firmware development since 1999 + \item IT security expert, focus on network protocol security + \item Core developer of Linux packet filter netfilter/iptables + \item Trained as Electrical Engineer + \item Always looking for interesting protocols (RFID, DECT, GSM) +\end{itemize} +\end{frame} + +\begin{frame}{Success of Free Software}{depending on area of computing} +\begin{itemize} + \item Free Software has proven to be successful in many areas of +computing + \begin{itemize} + \item Operating Systems (GNU/Linux) + \item Internet Servers (Apache, Sendmail, Exim, Cyrus, +...) + \item Desktop Computers (gnome, KDE, Firefox, LibreOffice, ...) + \item Mobile Devices + \item Embedded network devices (Router, Firewall, NAT, WiFi-AP) + \end{itemize} + \item There are more areas to computing that people tend to +forget. Examples in the communications area: + \begin{itemize} + \item Cellular telephony networks (GSM, 3G, LTE) + \item Professional Mobile Radio (TETRA, TETRAPOL) + \item Cordless telephones (DECT) + \end{itemize} +\end{itemize} +\end{frame} + +\include{part-security_research} + +\begin{frame}{Security analysis of GSM}{The bootstrapping process} +\begin{itemize} + \item Start to read GSM specs (> 1000 PDF documents!) + \item Gradually grow knowledge about the protocols + \item Obtain actual GSM network equipment (BTS) + \item Try to get actual protocol traces as examples + \item Start a complete protocol stack implementation from scratch + \item Finally, go and play with GSM protocol security +\end{itemize} +\end{frame} + +\subsection{The GSM network} + +\begin{frame}{The GSM network} + \begin{figure}[h] + \centering + \includegraphics[width=100mm]{gsm_network.png} + \end{figure} +\end{frame} + +\begin{frame}{GSM network components} + \begin{itemize} + \item The BSS (Base Station Subsystem) + \begin{itemize} + \item MS (Mobile Station): Your phone + \item BTS (Base Transceiver Station): The {\em cell tower} + \item BSC (Base Station Controller): Controlling up to hundreds of BTS + \end{itemize} + \item The NSS (Network Sub System) + \begin{itemize} + \item MSC (Mobile Switching Center): The central switch + \item HLR (Home Location Register): Database of subscribers + \item AUC (Authentication Center): Database of authentication keys + \item VLR (Visitor Location Register): For roaming users + \item EIR (Equipment Identity Register): To block stolen phones + \end{itemize} + \end{itemize} +\end{frame} + +\begin{frame}{GSM network interfaces} + \begin{itemize} + \item Um: Interface between MS and BTS + \begin{itemize} + \item the only interface that is specified over radio + \end{itemize} + \item A-bis: Interface between BTS and BSC + \item A: Interface between BSC and MSC + \item B: Interface between MSC and other MSC + \end{itemize} + GSM networks are a prime example of an asymmetric distributed network, + very different from the end-to-end transparent IP network. +\end{frame} + + +\subsection{The GSM protocols} + +\begin{frame}{GSM network protocols}{On the Um interface} + \begin{itemize} + \item Layer 1: Radio Layer, TS 04.04 + \item Layer 2: LAPDm, TS 04.06 + \item Layer 3: Radio Resource, Mobility Management, Call Control: TS 04.08 + \item Layer 4+: for USSD, SMS, LCS, ... + \end{itemize} +\end{frame} + +\begin{frame}{GSM network protocols}{On the A-bis interface} + \begin{itemize} + \item Layer 1: Typically E1 line, TS 08.54 + \item Layer 2: A variant of ISDN LAPD with fixed TEI's, TS 08.56 + \item Layer 3: OML (Organization and Maintenance Layer, TS 12.21) + \item Layer 3: RSL (Radio Signalling Link, TS 08.58) + \item Layer 4+: transparent messages that are sent to the MS via Um + \end{itemize} +\end{frame} + +\include{section-openbsc} + +\include{section-osmocombb} + +\include{section-openbts} +\include{section-airprobe} +\include{section-wireshark} + +%\section{Summary} +%\subsection{What we've learned} + +\begin{frame}{Summary}{What we've learned} +\begin{itemize} + \item The GSM industry is making security analysis very difficult + \item It is well-known that the security level of the GSM stacks is very low + \item We now have multiple solutions for sending arbitrary protocol data + \begin{itemize} + \item From a rogue network to phones (OpenBSC, OpenBTS) + \item From a FOSS controlled phone to the network (OsmocomBB) + \item From an A-bis proxy to the network or the phones + \end{itemize} +\end{itemize} +\end{frame} + +\subsection{Where we go from here} + +\begin{frame}{TODO}{Where we go from here} +\begin{itemize} + \item The tools for fuzzing mobile phone protocol stacks are available + \item It is up to the security community to make use of those tools (!) + \item Don't you too think that TCP/IP security is boring? + \item Join the GSM protocol security research projects + \item Boldly go where no (free) man has gone before +\end{itemize} +\end{frame} + +\begin{frame}{Current Areas of Work / Future plans} +\begin{itemize} + \item UMTS(3G) support for NodeB and femtocells + \item SS7 / MAP integration (Erlang and C) + \item Playing with SIM Toolkit from the operator side + \item Playing with MMS + \item More exploration of RRLP + SUPL +\end{itemize} +\end{frame} + +%\subsection{Further Reading} + +\begin{frame}{Further Reading} +\begin{itemize} + \item \url{http://laforge.gnumonks.org/papers/gsm_phone-anatomy-latest.pdf} + \item \url{http://bb.osmocom.org/} + \item \url{http://openbsc.osmocom.org/} + \item \url{http://openbts.sourceforge.net/} + \item \url{http://airprobe.org/} +\end{itemize} +\end{frame} + +\end{document} diff --git a/2011/gsm-ensa2011/gsm.vrb b/2011/gsm-ensa2011/gsm.vrb new file mode 100644 index 0000000..d917a88 --- /dev/null +++ b/2011/gsm-ensa2011/gsm.vrb @@ -0,0 +1,13 @@ +\frametitle {OpenBTS USRP Clocking}\framesubtitle {Kalibrator Example} +\begin{block}{Example of running {\tt kal}} +\begin{lstlisting} +[openBTS@openBTS kal-0.2]# ./kal -f 946600000 -u +USRP side: B +FPGA clock: 52000000 +Decimation: 192 +Antenna: RX2 +Sample rate: 270833.343750 +average [min, max] (range, stddev) -2197.789062 [-2431, -1843] (588, 146.761444) +\end{lstlisting} +\end{block} +The value {\bf -2198 should be used as FREQOFF constant in Transceiver/USRPDevice.cpp} diff --git a/2011/gsm-ensa2011/gsm_network.png b/2011/gsm-ensa2011/gsm_network.png Binary files differnew file mode 100644 index 0000000..c5f6399 --- /dev/null +++ b/2011/gsm-ensa2011/gsm_network.png diff --git a/2011/gsm-ensa2011/openbsc_host.jpg b/2011/gsm-ensa2011/openbsc_host.jpg Binary files differnew file mode 100644 index 0000000..10c575d --- /dev/null +++ b/2011/gsm-ensa2011/openbsc_host.jpg diff --git a/2011/gsm-ensa2011/osmosgsn.png b/2011/gsm-ensa2011/osmosgsn.png Binary files differnew file mode 100644 index 0000000..f1dbc85 --- /dev/null +++ b/2011/gsm-ensa2011/osmosgsn.png diff --git a/2011/gsm-ensa2011/part-security_research.tex b/2011/gsm-ensa2011/part-security_research.tex new file mode 100644 index 0000000..676a4f5 --- /dev/null +++ b/2011/gsm-ensa2011/part-security_research.tex @@ -0,0 +1,141 @@ +%\part{Security Research} +\section{Researching GSM/3G security} +%\begin{frame}{Part 3 -- Researching GSM/3G security} +%\tableofcontents +% You might wish to add the option [pausesections] +%\end{frame} + +%\subsection{An interesting observation} + +\begin{frame}{Free specs / Free implementations} +\begin{itemize} + \item Observation + \begin{itemize} + \item Both GSM/3G and TCP/IP protocol specs are publicly available + \item The Internet protocol stack (Ethernet/Wifi/TCP/IP) receives lots of scrutiny + \item GSM networks are as widely deployed as the Internet + \item Yet, GSM/3G protocols receive no such scrutiny! + \end{itemize} + \item There are reasons for that: + \begin{itemize} + \item GSM industry is extremely closed (and closed-minded) + \item Only about 4 proprietary protocol stack implementations + \item GSM chip set makers never release any hardware documentation + \end{itemize} +\end{itemize} +\end{frame} + +\subsection{The closed GSM industry} + +\begin{frame}{The closed GSM industry}{Handset manufacturing side} +\begin{itemize} + \item Only very few companies build GSM/3.5G baseband chips today + \begin{itemize} + \item Those companies buy the operating system kernel and the protocol stack from third parties + \end{itemize} + \item Only very few handset makers are large enough to become a customer + \begin{itemize} + \item Even they only get limited access to hardware documentation + \item Even they never really get access to the firmware source + \end{itemize} +\end{itemize} +\end{frame} + +%\subsection{The closed GSM industry -- Network side} + +\begin{frame}{The closed GSM industry}{Network manufacturing side} +\begin{itemize} + \item Only very few companies build GSM network equipment + \begin{itemize} + \item Basically only Ericsson, Nokia-Siemens, Alcatel-Lucent and Huawei + \item Exception: Small equipment manufacturers for picocell / nanocell / femtocells / measurement devices and law enforcement equipment + \end{itemize} + \item Only operators buy equipment from them + \item Since the quantities are low, the prices are extremely high + \begin{itemize} + \item e.g. for a BTS, easily 10-40k EUR + \item minimal network using standard components definitely in the 100,000s of EUR range + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{The closed GSM industry}{Operator side} +From my experience with Operators (prove me wrong!) +\begin{itemize} + \item Operators are mainly finance + marketing today + \item Many operators outsources + \begin{itemize} + \item Network servicing / deployment, even planning + \item Other aspects of business like Billing + \end{itemize} + \item Operator just knows the closed equipment as shipped by manufacturer + \item Very few people at an operator have knowledge of the protocol beyond what's needed for operations and maintenance +\end{itemize} +\end{frame} + +\subsection{Security implications} + +\begin{frame}{The closed GSM industry}{Security implications} +The security implications of the closed GSM industry are: +\begin{itemize} + \item Almost no people who have detailed technical knowledge outside the protocol stack or GSM network equipment manufacturers + \item No independent research on protocol-level security + \begin{itemize} + \item If there's security research at all, then only theoretical (like the A5/2 and A5/1 cryptanalysis) + \item Or on application level (e.g. mobile malware) + \end{itemize} + \item No free software protocol implementations + \begin{itemize} + \item which are key for making more people learn about the protocols + \item which enable quick prototyping/testing by modifying existing code + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{Security analysis of GSM}{How would you get started?} +If you were to start with GSM protocol level security analysis, where and +how would you start? +\begin{itemize} + \item On the handset side? + \begin{itemize} + \item Difficult since GSM firmware and protocol stacks are closed and proprietary + \item Even if you want to write your own protocol stack, the layer 1 hardware and signal processing is closed and undocumented, too + \item Known attempts + \begin{itemize} + \item The TSM30 project as part of the THC GSM project + \item MADos, an alternative OS for Nokia DTC3 phones + \end{itemize} + \item none of those projects successful so far + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{Security analysis of GSM}{How would you get started?} +If you were to start with GSM protocol level security analysis, where and +how would you start? +\begin{itemize} + \item On the network side? + \begin{itemize} + \item Difficult since equipment is not easily available and normally extremely expensive + \item However, network is very modular and has many standardized/documented interfaces + \item Thus, if equipment is available, much easier/faster progress + \item Also, using SDR (software defined radio) approach, special-purpose / closed hardware can be avoided + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{Security analysis of GSM}{The bootstrapping process} +\begin{itemize} + \item Read GSM specs day and night (> 1000 PDF documents) + \item Gradually grow knowledge about the protocols + \begin{itemize} + \item OpenBSC: Obtain actual GSM network equipment (BTS) + \item OpenBTS: Develop SDR based GSM Um Layer 1 + \end{itemize} + \item Try to get actual protocol traces as examples + \item Start a complete protocol stack implementation from scratch + \item Finally, go and play with GSM protocol security +\end{itemize} +\end{frame} + + diff --git a/2011/gsm-ensa2011/section-airprobe.tex b/2011/gsm-ensa2011/section-airprobe.tex new file mode 100644 index 0000000..526e317 --- /dev/null +++ b/2011/gsm-ensa2011/section-airprobe.tex @@ -0,0 +1,33 @@ +\subsection{airprobe} + +\begin{frame}{Open Source GSM Tools: Airprobe} +\begin{itemize} + \item {\em airprobe} is a collection of Um protocol analyzer tools using the USRP software defined radio + \item A number of different Um receiver implementations + \begin{description}[gsm-receiver] + \item[gssm] One of the two early Um receiver implementations (M\&M clock recovery) + \item[gsmsp] The other early Um receiver implementation + \item[gsm-tvoid] For a long time the Um receiver with best performance + \item[gsm-receiver] The latest generation of Um receiver + \end{description} + \item Today, gsm-receiver seems to be the most popular choice +\end{itemize} +\end{frame} + +\begin{frame}{Open Source GSM Tools: Airprobe} +\begin{itemize} + \item Some other airprobe tools + \begin{description}[viterbi\_gen] + \item[gsmdecode] A standalone text-mode Um L2 frame parser + \item[wireshark] Dissector code for feeding Um frames into wireshark + \item[gsmstack] An unfinished more modular implementation of a Rx-only L1 + \item[viterbi\_gen] Generate C++ implementations of a viterbi decoder + \end{description} + \item Still under development, no user friendly solution + \begin{itemize} + \item gsmtap frame format needs to be added as clean wireshark interface + \item receivers need automatic frequency scanning + \item full solution needs proper UI + \end{itemize} +\end{itemize} +\end{frame} diff --git a/2011/gsm-ensa2011/section-openbsc.tex b/2011/gsm-ensa2011/section-openbsc.tex new file mode 100644 index 0000000..3095cd9 --- /dev/null +++ b/2011/gsm-ensa2011/section-openbsc.tex @@ -0,0 +1,208 @@ +\section{OpenBSC} + +\subsection{OpenBSC Introduction} + +\begin{frame}{OpenBSC software} +OpenBSC is a Open Source implementation of (not only) the BSC features +of a GSM network. +\begin{itemize} + \item Support A-bis interface over E1 and IP + \item Support for BTS vendor/model is modular, currently Siemens BS-11 and ip.access nanoBTS + \item Multiple BTS models/vendors can be mixed! + \item Can work as a {\em pure BSC} or as a full {\em network in a box} + \item Supports mobility management, authentication, intra-BSC hand-over, SMS, voice calls (FR/EFR/AMR) + \item GPRS + EDGE support if combined with OsmoSGSN and OpenGGSN +\end{itemize} +\end{frame} + +\begin{frame}{OpenBSC} +\begin{itemize} + \item Supports Siemens BS-11 BTS (E1) and ip.access nanoBTS (IP based) + \item Has classic 2G signalling, voice and SMS support + \item Implements various GSM protocols like + \begin{itemize} + \item A-bis RSL (TS 08.58) and OML (TS 12.21) + \item TS 04.08 Radio Resource, Mobility Management, Call Control + \item TS 04.11 Short Message Service + \end{itemize} + \item Telnet console with Cisco-style interface +\end{itemize} +\end{frame} + +\begin{frame}{OpenBSC software architecture} +\begin{itemize} + \item Implemented in pure C, similarities to Linux kernel + \begin{itemize} + \item Linked List handling, Timer API, coding style + \end{itemize} + \item Single-threaded event-loop / state machine design + \item Telnet based command line interface {\em Cisco-style} + \item Input driver abstraction (mISDN, Abis-over-IP) +\end{itemize} +\end{frame} + +\begin{frame}{OpenBSC: GSM network protocols}{The A-bis interface} + \begin{description}[Layer 4+] + \item[Layer 1] Typically E1 line, TS 08.54 + \item[Layer 2] A variant of ISDN LAPD with fixed TEI's, TS 08.56 + \item[Layer 3] OML (Organization and Maintenance Layer, TS 12.21) + \item[Layer 3] RSL (Radio Signalling Link, TS 08.58) + \item[Layer 4+] transparent messages that are sent to the MS via Um + \end{description} +\end{frame} + +\begin{frame}{OpenBSC: How it all started} +\begin{itemize} + \item In 2006, I bought a Siemens BS-11 microBTS on eBay + \begin{itemize} + \item This is GSM900 BTS with 2 TRX at 2W output power (each) + \item A 48kg monster with attached antenna + \item 200W power consumption, passive cooling + \item E1 physical interface + \end{itemize} + \item I didn't have much time at the time (day job at Openmoko) + \item Started to read up on GSM specs whenever I could + \item Bought a HFC-E1 based PCI E1 controller, has mISDN kernel support + \item Found somebody in the GSM industry who provided protocol traces +\end{itemize} +\end{frame} + +\begin{frame}{OpenBSC: Timeline} +\begin{itemize} + \item November 2008: I started the development of OpenBSC + \item December 2008: we did a first demo at 25C3 + \item January 2009: we had full voice call support + \item Q1/2009: Add support for ip.access nanoBTS + \item June 2009: I started with actual security related stuff + \item August 2009: We had the first field test with 2BTS and > 860 phones + \item Q1/2010: The first 25 OpenBSC instances running in a commercial network +\end{itemize} +\end{frame} + +\begin{frame}{OpenBSC: Field Test at HAR2009} +\begin{figure}[h] +\subfigure{\includegraphics[width=5cm]{bts_tree_full.jpg}} +\subfigure{\includegraphics[width=5cm]{openbsc_host.jpg}} +\end{figure} +\end{frame} + + +\subsection{OpenBSC Network In The Box} + +\begin{frame}{OpenBSC in NITB mode}{Network In a Box Mode} +The {\tt osmo-nitb} program +\begin{itemize} + \item implements the A-bis interface towards any number of BTS + \item provides most typical features of a GSM network in one software + \item no need for MSC, AuC, HLR, VLR, EIR, ... + \begin{itemize} + \item HLR/VLR as SQLite3 table + \item Authentication + Ciphering support + \item GSM voice calls, MO/MT SMS + \item Hand-over between all BTS + \item Multiple Location Areas within one BSC + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{OpenBSC NITB features} +OpenBSC NITB features +\begin{itemize} + \item Run a small GSM network with 1-n BTS and OpenBSC + \item No need for MSC/HLR/AUC/... + \item No need for your own SIM cards (unless crypto/auth rqd) + \item Establish signalling and voice channels + \item Make incoming and outgoing voice calls between phones + \item Send/receive SMS between phones + \item Connect to ISDN PBX or public ISDN via Linux Call Router +\end{itemize} +\end{frame} + +\begin{frame}{OpenBSC in NITB mode}{Network In a Box Mode} +The {\tt osmo-nitb} program +\begin{itemize} + \item does not implement any other GSM interfaces apart from A-bis + \item no SS7 / TCAP / MAP based protocols + \item no integration (roaming) with existing traditional GSM networks + \item wired telephony interfacing with ISDN PBX {\tt lcr} (Linux Call Router) + \item Has been tested with up to 800 subscribers on 5 BTS + \item Intended for R\&D use or private PBX systems +\end{itemize} +\end{frame} + +\begin{frame}{OpenBSC LCR integration}{Interfacing with wired telephony} +OpenBSC (NITB mode) can be linked into Linux Call Router ({\tt lcr}) +\begin{itemize} + \item OpenBSC is compiled as libbsc.a + \item libbsc.a includes full OpenBSC NITB mod code + \item linking the library into {\tt lcr} results in GSM {\em line interfaces} to become available inside {\tt lcr} + \item OpenBSC no longer takes care of call control, but simply hands everything off to {\tt lcr} + \item Dialling plan, etc. is now configure in {\tt lcr} like for any other wired phones +\end{itemize} +\end{frame} + +\subsection{OpenBSC BSC-only mode} + +\begin{frame}{OpenBSC in BSC-only mode} +The {\tt osmo-bsc} program +\begin{itemize} + \item behaves like a classic GSM BSC + \item uses SCCP-Lite (ip.access multipex) to any SoftMSC like ADC + \item used in production/commercial deployments (~ 75 BSCs) + \item mainly intended to replace proprietary BSC in traditional GSM networks +\end{itemize} +\end{frame} + +%\begin{frame}<handout:0>{OpenBSC} +% Demonstration +%\end{frame} + +\subsection{OpenBSC GPRS support} + +\begin{frame}{GPRS and OpenBSC} +\begin{itemize} + \item The BSC doesn't really do anything related to GPRS + \item GPRS implemented in separate SGSN and GGSN nodes + \item GPRS uses its own Gb interface to RAN, independent of A-bis + \item OpenBSC can configure the nanoBTS for GPRS+EDGE support via OML + \item Actual SGSN and GGSN implemented as OsmoSGSN and OpenGGSN programs +\end{itemize} +\end{frame} + +\begin{frame}{OsmoSGSN} +The Osmocom SGSN program implements +\begin{itemize} + \item basic/minimal SGSN functionality + \item the Gb interface (NS/BSSGP/LLC/SNDCP) + \item mobility management, session management +\end{itemize} +It's a work in progress, many missing features +\begin{itemize} + \item no HLR integration yet + \item no paging coordination with MSC/BSC + \item no encryption support yet +\end{itemize} +\end{frame} + +\begin{frame}{OpenGGSN} +\begin{itemize} + \item GPL licensed Linux program implementing GGSN node + \item Implements GTP-U protocol between SGSN and GGSN + \item User-configurable range/pool of IPv4 addresses for MS + \item Uses {\tt tun} device for terminating IP tunnel from MS + \item provides GTP implementation as libgtp + \item Experimental patches for IPv6 support +\end{itemize} +\end{frame} + +%\begin{frame}<handout:0>{OpenBSC + OpenGGSN + OsmoSGSN} +% Demonstration +%\end{frame} + +\begin{frame}{OpenBSC and OsmoSGSN based network} +\begin{figure}[h] +\includegraphics[width=10cm]{osmosgsn.png} +\end{figure} +\end{frame} + +% FIXME: include slide showing full OpenBSC+OsmoSGSN+OpenGGSN network diff --git a/2011/gsm-ensa2011/section-openbts.tex b/2011/gsm-ensa2011/section-openbts.tex new file mode 100644 index 0000000..9c04222 --- /dev/null +++ b/2011/gsm-ensa2011/section-openbts.tex @@ -0,0 +1,183 @@ +\section{OpenBTS, airprobe and wireshark} + +\subsection{OpenBTS Introduction} + +\begin{frame}{What is OpenBTS?} +\begin{itemize} + \item is {\em NOT} a BTS in the typical GSM sense + \item is better described as a GSM-Um to SIP gateway + \item implements the GSM Um (air interface) as SDR + \item uses the USRP hardware as RF interface + \item does not implement any of BSC, MSC, HLR, etc. + \item bridges the GSM Layer3 protocol onto SIP + \item uses SIP switch (like Asterisk) for switching calls + SMS + \item is developed as C++ program and runs on Linux + MacOS +\end{itemize} +\end{frame} + +\begin{frame}{What is OpenBTS?} +\begin{itemize} + \item Open implementation of Um L1 \& L2, an all-software BTS. + \item L1/L2 design based on an object-oriented dataflow approach. + \item Includes L3 RR functions normally found in BSC. + \item Uses SIP PBX for MM and CC functions, eliminating the conventional GSM network. L3 is like an ISDN/SIP gateway. + \item Intended for use in low-cost and rapidly-deployed communications networks, but can be used for experiments (including by Chris Paget at Def Con). +\end{itemize} +\end{frame} + +\begin{frame}{OpenBTS Hardware} +OpenBTS supports the following SDR hardware +\begin{itemize} + \item Ettus USRP(1) with two RFX 900 or RFX 1800 daughter boards + \begin{itemize} + \item Modification for external clock input recommended + \item External 52 MHz precision clock recommended + \end{itemize} + \item Kestrel Signal Processing / Range Networks custom radio + \item Close Haul Communications / GAPfiller (work in progress) + \item Ported to other radios by other clients +\end{itemize} +\end{frame} + + +\begin{frame}{OpenBTS History + Tests} +\begin{itemize} + \item Started work in August 2007, first call in January 2008, first SMS in December 2008. + \item First public release in September 2008, assigned to FSF in October 2008. + \item Tested 3-sector system with 10,000-20,000 handsets at September 2009 Burning Man event in Nevada. + \item Tested 2-sector system with 40,000 handsets at September 2010 Burning Man event in Nevada. + \item Release 2.5 is about 13k lines of C++. + \item Part of GNU Radio project, distributed under GPLv3 (>= 2.6: AGPLv3) +\end{itemize} +\end{frame} + +\begin{frame}{OpenBTS Software Architecture} +\begin{itemize} + \item {\tt Transceiver} program + \begin{itemize} + \item SDR processing for Layer 0 + \item BTS-side GSM Um Layer 1 implementation + \item sends GSM burst data via UDP socket + \end{itemize} + \item {\tt OpenBTS} program + \begin{itemize} + \item GSM Um Layer 2 (04.06) + 3 (04.08) implementation + \item SIP UA implementation + \item GSM Layer 3 CC to SIP bridge implementation + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{OpenBTS GSM <-> SIP mapping} +\begin{itemize} + \item Location Updates mapped to SIP registration + \begin{itemize} + \item Use IMSI as SIP user name + \end{itemize} + \item Call Control mapped to SIP transactions + \begin{itemize} + \item relatively straight-forward + \end{itemize} + \item GSM Traffic Channels mapped to RTP channels + \begin{itemize} + \item No transcoding inside OpenBTS, FR/EFR messages are simply relayed + \end{itemize} + \item SMS mapped to SIP messaging according to RFC 3428 + \begin{itemize} + \item A separate {\tt smqueue} daemon implements store+forward + \end{itemize} +\end{itemize} +\end{frame} + +%\subsection{Clocking} + +\begin{frame}{OpenBTS USRP Clocking}{Clock Stability} +\begin{itemize} + \item USRP has regular XO (Crystal Oscillator) with 20ppm accuracy + \item GSM requires 20ppb carrier clock accuracy + \item possible solutions + \begin{itemize} + \item use external VCTCXO clocking module + \item use external OCXO clocking module + \item use a software calibration program comparing USRP XO with real GSM BTS carrier clocks + \end{itemize} + \item due to clock multiplication, absolute error in GSM1800 is higher than in GSM900 +\end{itemize} +\end{frame} + + +\begin{frame}{OpenBTS USRP Clocking}{64 MHz vs. 52 MHz clock} +\begin{itemize} + \item The USRP master clock is 64 Mhz + \item In GSM, all clocks are derived from 13 MHz + \item Thus, a poly-phase re-sampler is part of SDR software + \item Alternative: use 52 MHz (13 MHz * 4) external clock + \item OpenBTS has two transceiver programs, one for each 64 MHz and 52 MHz + \begin{itemize} + \item Make sure to never use the wrong transceiver for your clock! + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{OpenBTS USRP Clocking}{Software Calibration} +Basic idea: Use real GSM cell as clock source +\begin{itemize} + \item Implemented by the {\em Kalibrator} ({\tt kal}) program + \item Acquire the FCCH burst of a real GSM cell + \item Measure the clock difference between USRP XO and that cell + \item Use the computed error as offset to USRP up/downconverter + \item However, temperature and other drift will make clocks go out of sync over time + \item Can only be used if a real-world GSM network is within range +\end{itemize} +\end{frame} + +%\begin{frame}[fragile]{OpenBTS USRP Clocking}{Kalibrator Example} +%\begin{block}{Example of running {\tt kal}} +%\begin{lstlisting} +%[openBTS@openBTS kal-0.2]# ./kal -f 946600000 -u +%USRP side: B +%FPGA clock: 52000000 +%Decimation: 192 +%Antenna: RX2 +%Sample rate: 270833.343750 +%average [min, max] (range, stddev) -2197.789062 [-2431, -1843] (588, 146.761444) +%\end{lstlisting} +%\end{block} +%The value {\bf -2198 should be used as FREQOFF constant in Transceiver/USRPDevice.cpp} +%\end{frame} + +\begin{frame}{OpenBTS -- ``Nevada Test Site'' \& 21m Mast} +\begin{figure}[h] + \centering + \includegraphics[width=85mm]{NevadaTestSite.jpg} +\end{figure} +\end{frame} + +\begin{frame}{Burning Man 2010 Tower Base} +\begin{figure}[h] + \centering + \includegraphics[width=85mm]{OBTSBM2010.jpg} +\end{figure} +\end{frame} + +%\begin{frame}<handout:0>{OpenBTS} +% Demonstration +%\end{frame} + +\begin{frame}{OpenMS} +\begin{itemize} + \item Subscriber side stack based on OpenBTS. + \item Called MS, but just a BTS stack with data flows reversed and a different RR control logic. + \item Behavior is more like a passive interceptor that can also transmit. + \item Release 1.0 supports non-hopping multi-ARFCN networks. + \item Most L3 control logic provided by the end user. + \item A platform for + \begin{itemize} + \item passive interceptors + \item custom subscriber-side applications + \item environment analysis + \item intelligent jamming + \end{itemize} + \item NOT Open Source +\end{itemize} +\end{frame} diff --git a/2011/gsm-ensa2011/section-osmocombb.tex b/2011/gsm-ensa2011/section-osmocombb.tex new file mode 100644 index 0000000..a8f4cd1 --- /dev/null +++ b/2011/gsm-ensa2011/section-osmocombb.tex @@ -0,0 +1,296 @@ +\section{OsmocomBB Project} + +\begin{frame}{A GSM phone baseband processor} +\begin{itemize} + \item GSM protocol stack always runs in a so-called baseband processor (BP) + \item What is the baseband processor + \begin{itemize} + \item Typically ARM7 (2G/2.5G phones) or ARM9 (3G/3.5G phones) + \begin{itemize} + \item Runs some RTOS (often Nucleus, sometimes L4) + \item No memory protection between tasks + \end{itemize} + \item Some kind of DSP, model depends on vendor + \begin{itemize} + \item Runs the digital signal processing for the RF Layer 1 + \item Has hardware peripherals for A5 encryption + \end{itemize} + \end{itemize} + \item The software stack on the baseband processor + \begin{itemize} + \item is written in C and assembly + \item lacks any modern security features (stack protection, non-executable pages, address space randomization, ..) + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{A GSM Baseband Chipset} + \begin{figure}[h] + \centering + \includegraphics[width=100mm]{calypso-block.pdf} + \end{figure} + \url{http://laforge.gnumonks.org/papers/gsm_phone-anatomy-latest.pdf} +\end{frame} + +\begin{frame}{Requirements for GSM security analysis} +What do we need for protocol-level security analysis? +\begin{itemize} + \item A GSM MS-side baseband chipset under our control + \item A Layer1 that we can use to generate arbitrary L1 frames + \item A Layer2 protocol implementation that we can use + modify + \item A Layer3 protocol implementation that we can use + modify +\end{itemize} +None of those components existed, so we need to create them! +\end{frame} + +\begin{frame}{A GSM baseband under our control} +The two different DIY approaches +\begin{itemize} + \item Build something using generic components (DSP, CPU, ADC, FPGA) + \begin{itemize} + \item No reverse engineering required + \item A lot of work in hardware design + debugging + \item Hardware will be low-quantity and thus expensive + \end{itemize} + \item Build something using existing baseband chipset + \begin{itemize} + \item Reverse engineering or leaked documents required + \item Less work on the 'Layer 0' + \item Still, custom hardware in low quantity + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{A GSM baseband under our control} +Alternative 'lazy' approach +\begin{itemize} + \item Re-purpose existing mobile phone + \begin{itemize} + \item Hardware is known to be working + \item No prototyping, hardware revisions, etc. + \item Reverse engineering required + \item Hardware drivers need to be written + \item But: More time to focus on the actual job: Protocol software + \end{itemize} + \item Searching for suitable phones + \begin{itemize} + \item As cheap as possible + \item Readily available: Many people can play with it + \item As old/simple as possible to keep complexity low + \item Baseband chipset with lots of leaked information + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{Baseband chips with leaked information} +\begin{itemize} + \item Texas Instruments Calypso + \begin{itemize} + \item DBB Documentation on cryptome.org and other sites + \item ABB Documentation on Chinese phone developer websites + \item Source code of GSM stack / drivers was on sf.net (tsm30 project) + \item End of life, no new phones with Calypso since about 2008 + \item No cryptographic checks in bootloader + \end{itemize} + \item Mediatek MT622x chipsets + \begin{itemize} + \item Lots of Documentation on Chinese sites + \item SDK with binary-only GSM stack libraries on Chinese sites + \item 95 million produced/sold in Q1/2010 + \end{itemize} +\end{itemize} +Initial choice: TI Calypso (GSM stack source available) +\end{frame} + + +\subsection{OsmocomBB Introduction} + +\begin{frame}{OsmocomBB Introduction} +\begin{itemize} + \item Project was started only in January 2010 (9 months ago!) + \item Implementing a GSM baseband software from scratch + \item This includes + \begin{itemize} + \item GSM MS-side protocol stack from Layer 1 through Layer 3 + \item Hardware drivers for GSM Baseband chipset + \item Simple User Interface on the phone itself + \item Verbose User Interface on the PC + \end{itemize} + \item Note about the strange project name + \begin{itemize} + \item Osmocom = Open Source MObile COMmunication + \item BB = Base Band + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{OsmocomBB Software Architecture} +\begin{itemize} + \item Reuse code from OpenBSC where possible (libosmocore) + \begin{itemize} + \item We build libosmocore both for phone firmware and PC + \end{itemize} + \item Initially run as little software in the phone + \begin{itemize} + \item Debugging code on your host PC is so much easier + \item You have much more screen real-estate + \item Hardware drivers and Layer1 run in the phone + \item Layer2, 3 and actual phone application / MMI on PC + \item Later, L2 and L3 can me moved to the phone + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{OsmocomBB Software Interfaces} +\begin{itemize} + \item Interface between Layer1 and Layer2 called L1CTL + \begin{itemize} + \item Fully custom protocol as there is no standard + \item Implemented as message based protocol over Sercomm/HDLC/RS232 + \end{itemize} + \item Interface between Layer2 and Layer3 called RSLms + \begin{itemize} + \item In the GSM network, Um Layer2 terminates at the BTS but is controlled by the BSC + \item Reuse this GSM 08.58 Radio Signalling Link + \item Extend it where needed for the MS case + \end{itemize} +\end{itemize} +\end{frame} + +\subsection{OsmocomBB Software} + +\begin{frame}{OsmocomBB Target Firmware} +\begin{itemize} + \item Firmware includes software like + \begin{itemize} + \item Drivers for the Ti Calypso Digital Baseband (DBB) + \item Drivers for the Ti Iota TWL3025 Analog Baseband (ABB) + \item Drivers for the Ti Rita TRF6151 RF Transceiver + \item Drivers for the LCD/LCM of a number of phones + \item CFI flash driver for NOR flash + \item GSM Layer1 synchronous/asynchronous part + \item Sercomm - A HDLC based multiplexer for the RS232 to host PC + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{OsmocomBB Host Software} +\begin{itemize} + \item Current working name: layer23 + \item Includes + \begin{itemize} + \item Layer 1 Control (L1CTL) protocol API + \item GSM Layer2 implementation (LAPDm) + \item GSM Layer3 implementation (RR/MM/CC) + \item GSM Cell (re)selection + \item SIM Card emulation + \item Supports various 'apps' depending on purpose + \end{itemize} +\end{itemize} +\end{frame} + +\subsection{OsmocomBB Hardware Support} + +\begin{frame}{OsmocomBB Supported Hardware} +\begin{itemize} + \item Baseband Chipsets + \begin{itemize} + \item TI Calypso/Iota/Rita + \item Some early research being done on Mediatek (MTK) MT622x + \end{itemize} + \item Actual Phones + \begin{itemize} + \item Compal/Motorola C11x, C12x, C13x, C14x and C15x models + \item Most development/testing on C123 and C155 + \item GSM modem part of Openmoko Neo1973 and Freerunner + \end{itemize} + \item All those phones are simple feature phones built on a ARM7TDMI based DBB +\end{itemize} +\end{frame} + +\begin{frame}{The Motorola/Compal C123} + \begin{figure}[h] + \centering + \includegraphics[width=100mm]{c123_pcb.jpg} + \end{figure} +\end{frame} + + +\subsection{OsmocomBB Project Status} + +\begin{frame}{OsmocomBB Project Status: Working} +\begin{itemize} + \item Hardware Drivers for Calypso/Iota/Rita very complete + \item Drivers for Audio/Voice signal path + \item Layer1 + \begin{itemize} + \item Power measurements + \item Carrier/bit/TDMA synchronization + \item Receive and transmit of normal bursts on SDCCH + \item Transmit of RACH bursts + \item Automatic Rx gain control (AGC) + \item Frequency Hopping + \end{itemize} + \item Layer2 UI/SABM/UA frames and ABM mode + \item Layer3 Messages for RR / MM / CC + \item Cell (re)selection according GSM 03.22 +\end{itemize} +\end{frame} + +\begin{frame}{OsmocomBB Project Status: Working (2/2)} +OsmocomBB can now do GSM Voice calls (since 08/2010) +\begin{itemize} + \item Very Early Assignment + Late Assignment + \item A3/A8 Authentication of SIM + \item A5/1 + A5/2 Encryption + \item Full Rate (FR) and Enhanced Full Rate (EFR) codec +\end{itemize} +\end{frame} + +\begin{frame}{OsmocomBB Project Status: Not working} +\begin{itemize} + \item Layer1 + \begin{itemize} + \item Automatic Tx power control (APC) + \item Neighbor Cell Measurements (WIP) + \item In-call hand-over to other cells (WIP) + \end{itemize} + \item Actual UI on the phone + \item Circuit Switched Data (CSD) calls + \item GPRS (packet data) + \item No Type Approval for the stack! +\end{itemize} +\end{frame} + +\begin{frame}{OsmocomBB Project Status: Executive Summary} +\begin{itemize} + \item We can establish control/signalling channels to both hopping and non-hopping GSM cells + \begin{itemize} + \item Control over synthesizer means we can even go to GSM-R band + \end{itemize} + \item We can send arbitrary data on those control channels + \begin{itemize} + \item RR messages to BSC + \item MM/CC messages to MSC + \item SMS messages to MSC/SMSC + \end{itemize} + \item TCH (Traffic Channel) support for voice calls + \begin{itemize} + \item Has been used on real networks for 30+ minute calls! + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{OsmocomBB use cases} +OsmocomBB can be used today for +\begin{itemize} + \item practical lab exercises in education on any level of GSM, +from the radio modem through the protocol stack + \item applied research in GSM protocols and GSM security + \item penetration testing of GSM operator equipment + \item measurement and exploration of real operator networks +\end{itemize} +With (your?) help, we can turn it into an actual mobile phone for +regular users, i.e. bringing the freedom of Free Software into one of +the most closed areas of computing. +\end{frame} diff --git a/2011/gsm-ensa2011/section-wireshark.tex b/2011/gsm-ensa2011/section-wireshark.tex new file mode 100644 index 0000000..a3ee9c6 --- /dev/null +++ b/2011/gsm-ensa2011/section-wireshark.tex @@ -0,0 +1,35 @@ +\subsection{wireshark Protocol Analyzer} + +\begin{frame}{The wireshark protocol analyzer} +\begin{itemize} + \item Software protocol analyzer for plethora of protocols + \item Portable, works on most flavors of Unix and Windows + \item Decode, display, search and filter packets with configurable level of detail + \item Over 1000 protocol decoders + \item Over 86000 display filters + \item Live capturing from many different network media + \item Import files from other capture programs + \item Used to be called ethereal, but is now called wireshark +\item \url{http://www.wireshark.org/} +\item \url{http://www.wireshark.org/download/docs/user-guide-a4.pdf} +\end{itemize} +\end{frame} + +\begin{frame}{The wireshark protocol analyzer} +GSM protocol dissectors in wireshark +\begin{itemize} + \item TCP/IP (transport layer for Abis/IP) + \item E1 Layer 2 (LAPD) + \item GSM Um Layer 2 (LAPDm) + \item GSM Layer 3 (RR, MM, CC) + \item A-bis Layer 3 (RSL) + \begin{itemize} + \item A-bis OML for Siemens and ip.access in OpenBSC git + \end{itemize} + \item GSMTAP pseudo-header (airprobe, OpenBTS, OsmocomBB) +\end{itemize} +\end{frame} + +%\begin{frame}<handout:0>{The wireshark protocol analyzer} +% Demonstration +%\end{frame} |
