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diff --git a/2010/gsm_security-dc2010/abstract.txt b/2010/gsm_security-dc2010/abstract.txt
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+GSM security nightmares : experiences from running own GSM network 
diff --git a/2010/gsm_security-dc2010/gsm_network.png b/2010/gsm_security-dc2010/gsm_network.png
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diff --git a/2010/gsm_security-dc2010/gsm_security-openbsc.pdf b/2010/gsm_security-dc2010/gsm_security-openbsc.pdf
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diff --git a/2010/gsm_security-dc2010/gsm_security-openbsc.snm b/2010/gsm_security-dc2010/gsm_security-openbsc.snm
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diff --git a/2010/gsm_security-dc2010/gsm_security-openbsc.tex b/2010/gsm_security-dc2010/gsm_security-openbsc.tex
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+% $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}
+
+% 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}
+% 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{GSM security nightmares}
+
+\subtitle
+{Running your own GSM network with OpenBSC}
+
+\author{Harald Welte}
+
+\institute
+{gnumonks.org\\gpl-violations.org\\OpenBSC\\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[DORS/CLUC 2010] % (optional, should be abbreviation of conference name)
+{DORS/CLUC 2010, May 2010, Zagreb/Croatia}
+% - 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
+  % 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 Linux since 1994
+	\item Kernel / bootloader / driver / firmware development since 1999
+	\item IT security specialist, focus on network protocol security
+	\item Board-level Electrical Engineering
+	\item Always looking for interesting protocols (RFID, DECT, GSM)
+\end{itemize}
+\end{frame}
+
+\section{GSM/3G security}
+
+\begin{frame}{GSM/3G protocol security}
+\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 closed-source protocol stack implementations
+		\item GSM chipset 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}
+
+\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
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\begin{frame}{The closed GSM industry}{Operator side}
+\begin{itemize}
+	\item Operators are mainly banks today
+	\item Typical operator outsources
+	\begin{itemize}
+		\item Billing
+		\item Network planning / deployment / servicing
+	\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 open source 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
+	\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
+	\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}
+
+
+\section{Implementing GSM protocols} 
+
+\subsection{Getting started}
+
+\begin{frame}{Implementing GSM protocols}{How I got started!}
+\begin{itemize}
+	\item In September 2008, we were first able to make the BTS active and see it on a phone
+	\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}
+
+\subsection{Timeline}
+
+\begin{frame}{Implementing GSM protocols}{Timeline}
+\begin{itemize}
+	\item In November 2008, I started the development of OpenBSC
+	\item In December 2008, we did a first demo at 25C3
+	\item In January 2009, we had full voice call support
+	\item In June 2009, I started with actual security related stuff
+	\item In August 2009, we had the first field test with 2BTS and > 860 phones
+\end{itemize}
+\end{frame}
+
+\subsection{OpenBSC}
+
+\begin{frame}{Security analysis of GSM}{OpenBSC}
+What is OpenBSC
+\begin{itemize}
+	\item A {\em GSM network in a box} software
+	\item Implements minimal subset of BSC, MSC, HLR, SMSC
+	\item Is Free and Open Source Software licensed under GNU GPL
+	\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}
+\end{itemize}
+\end{frame}
+
+\section{Security analysis}
+
+\subsection{Theory}
+
+\begin{frame}{Known GSM security problems}{Scientific papers, etc}
+\begin{itemize}
+	\item No mutual authentication between phone and network
+	\begin{itemize}
+		\item leads to rogue network attacks
+		\item leads to man-in-the-middle attacks
+		\item is what enables IMSI-catchers
+	\end{itemize}
+	\item Weak encryption algorithms
+	\item Encryption is optional, user does never know when it's active or not
+	\item DoS of the RACH by means of channel request flooding
+	\item RRLP (Radio Resource Location Protocol)
+	\begin{itemize}
+		\item the network can obtain GPS fix or even raw GSM data from the phone
+		\item combine that with the network not needing to authenticate itself
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\subsection{The Baseband}
+
+\begin{frame}{Known GSM security problems}{The Baseband side}
+\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}
+
+\subsection{Observations}
+
+\begin{frame}{Interesting observations}{Learned from implementing the stack}
+While developing OpenBSC, we observed a number of interesting
+\begin{itemize}
+	\item Many phones use their TMSI from the old network when they roam to a new network
+	\item Various phones crash when confronted with incorrect messages.  We didn't even start to intentionally send incorrect messages (!)
+	\item There are tons of obscure options on the GSM spec which no real network uses.  Potential attack vector by using rarely tested code paths.
+\end{itemize}
+\end{frame}
+
+\subsection{GSM Protocol Fuzzing}
+
+\begin{frame}{GSM Protocol Fuzzing}{Theoretical basis}
+How to do GSM protocol fuzzing
+\begin{itemize}
+	\item From the handset to the network
+	\begin{itemize}
+		\item Basically impossible due to closeness of baseband
+		\item However, some incomplete projects working on it
+	\end{itemize}
+	\item From the network side
+	\begin{itemize}
+		\item Easy in case of {\em rogue network} attacks
+		\item Fuzzing target is the GSM stack in the baseband processor
+	\end{itemize}
+	\item As an A-bis man in the middle
+	\begin{itemize}
+		\item Needs access to an A-bis interface of an actual network
+		\item Very attractive, since no encryption and ability to fuzz both network and handset
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\begin{frame}{A-bis injection}{for A-bis over IP}
+How to do inject messages into A-bis over IP?
+\begin{itemize}
+	\item Problem
+	\begin{itemize}
+		\item A-bis/IP uses one TCP connection for OML and RSL messages
+		\item OML initialization is essential for BTS to become operational
+		\item TCP makes insertion of additional messages relatively hard
+	\end{itemize}
+	\item Solution: Build an {\em A-bis injection proxy}
+	\begin{itemize}
+		\item Transparently pass OML and RSL packets between BTS and BSC
+		\item Add additional stateless UDP sockets for injecting messages, one socket each for
+	\end{itemize}
+	\begin{itemize}
+		\item injecting OML/RSL to the network
+		\item injecting OML/RSL to the BTS
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\begin{frame}{A-bis Injection Proxy}{Principle of operation}
+\begin{itemize}
+	\item Proxy needs to be brought between BTS and BSC
+	\item Luckily, A-bis/IP SSL support not always used
+	\item Thus, physical access to the Ethernet link sufficient
+	\item Configure system with two interfaces
+	\begin{itemize}
+		\item BSC-facing interface has IP of BTS
+		\item BTS-facing interface has IP of BSC / default gw
+	\end{itemize}
+	\item BTS will make TCP connection to proxy
+	\item proxy will make independent TCP connection to BSC
+\end{itemize}
+\end{frame}
+
+\begin{frame}{scapy GSM support}{The actual fuzzing}
+How to actually craft the packets for the fuzzing
+\begin{itemize}
+	\item GSM has many, many protocols
+	\item Writing custom code will be a hard-coded special case for each of them
+	\item Solution: Use scapy and implement the GSM protocols as scapy "layers"
+	\begin{itemize}
+		\item IPA protocol header
+		\item RSL protocol layer
+		\item RLL data indication / data request
+		\item GSM 04.08 RR / MM / CC messages
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\begin{frame}{OpenBSC silent calls}{A more elegant fuzzing interface}
+\begin{itemize}
+	\item Injection at the A-bis level has many problems
+	\begin{itemize}
+		\item you can only do it while a call is active
+		\item you simply piggy-back on existing RR connections
+	\end{itemize}
+	\item The OpenBSC {\em silent call} feature can help
+	\begin{itemize}
+		\item we use OpenBSC to establish a RR connection
+		\item in the GSM master/slave model, the phone will not close a connection unless told to do so
+		\item we then send arbitrary data to the phone and receive its responses
+		\item this currently only works from within OpenBSC, but we'll provide UDP injection sockets soon
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\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 an a-bis proxy to the network or the phones
+	\end{itemize}
+	\item There is ongoing work for a phone-based tool to fuzz the network
+\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 man has gone before
+\end{itemize}
+\end{frame}
+
+\subsection{Where we go from here}
+
+\begin{frame}{Current Areas of Work / Future plans}
+\begin{itemize}
+	\item Packet data (GPRS/EDGE) support in OpenBSC
+	\begin{itemize}
+		\item GPRS/EDGE is used extensively on modern smartphones
+		\item Enables us to play on IP level with those phones without a heavily filtered operator network
+	\end{itemize}
+	\item UMTS(3G) support in OpenBSC
+	\item Access to MS side layer 1
+	\item Playing with SIM Toolkit from the operator side
+	\item Playing with MMS
+	\item More exploration of RRLP
+\end{itemize}
+\end{frame}
+
+\subsection{Further Reading}
+
+\begin{frame}{Further Reading}
+\begin{itemize}
+	\item http://openbsc.gnumonks.org/
+	\item http://airprobe.org/
+	\item http://openbts.sourceforge.net/
+	\item http://bb.osmocom.org/
+\end{itemize}
+\end{frame}
+
+\end{document}
diff --git a/2010/gsm_security-dc2010/gsm_security-openbsc.tex.bak b/2010/gsm_security-dc2010/gsm_security-openbsc.tex.bak
new file mode 100644
index 0000000..f536c55
--- /dev/null
+++ b/2010/gsm_security-dc2010/gsm_security-openbsc.tex.bak
@@ -0,0 +1,586 @@
+% $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}
+
+% 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}
+% 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{GSM security nightmares}
+
+\subtitle
+{Running your own GSM network with OpenBSC}
+
+\author{Harald Welte}
+
+\institute
+{gnumonks.org\\gpl-violations.org\\OpenBSC\\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[DORS/CLUC 2010] % (optional, should be abbreviation of conference name)
+{DORS/CLUC 2010, May 2010, Zagreb/Croatia}
+% - 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
+  % 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 Linux since 1994
+	\item Kernel / bootloader / driver / firmware development since 1999
+	\item IT security specialist, focus on network protocol security
+	\item Board-level Electrical Engineering
+	\item Always looking for interesting protocols (RFID, DECT, GSM)
+\end{itemize}
+\end{frame}
+
+\section{GSM/3G security}
+
+\begin{frame}{GSM/3G protocol security}
+\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 closed-source protocol stack implementations
+		\item GSM chipset 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}
+
+\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
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\begin{frame}{The closed GSM industry}{Operator side}
+\begin{itemize}
+	\item Operators are mainly banks today
+	\item Typical operator outsources
+	\begin{itemize}
+		\item Billing
+		\item Network planning / deployment / servicing
+	\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 open source 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
+	\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
+	\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}
+
+
+\section{Implementing GSM protocols} 
+
+\subsection{Getting started}
+
+\begin{frame}{Implementing GSM protocols}{How I got started!}
+\begin{itemize}
+	\item In September 2008, we were first able to make the BTS active and see it on a phone
+	\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}
+
+\subsection{Timeline}
+
+\begin{frame}{Implementing GSM protocols}{Timeline}
+\begin{itemize}
+	\item In November 2008, I started the development of OpenBSC
+	\item In December 2008, we did a first demo at 25C3
+	\item In January 2009, we had full voice call support
+	\item In June 2009, I started with actual security related stuff
+	\item In August 2009, we had the first field test with 2BTS and > 860 phones
+\end{itemize}
+\end{frame}
+
+\subsection{OpenBSC}
+
+\begin{frame}{Security analysis of GSM}{OpenBSC}
+What is OpenBSC
+\begin{itemize}
+	\item A {\em GSM network in a box} software
+	\item Implements minimal subset of BSC, MSC, HLR, SMSC
+	\item Is Free and Open Source Software licensed under GNU GPL
+	\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}
+\end{itemize}
+\end{frame}
+
+\section{Security analysis}
+
+\subsection{Theory}
+
+\begin{frame}{Known GSM security problems}{Scientific papers, etc}
+\begin{itemize}
+	\item No mutual authentication between phone and network
+	\begin{itemize}
+		\item leads to rogue network attacks
+		\item leads to man-in-the-middle attacks
+		\item is what enables IMSI-catchers
+	\end{itemize}
+	\item Weak encryption algorithms
+	\item Encryption is optional, user does never know when it's active or not
+	\item DoS of the RACH by means of channel request flooding
+	\item RRLP (Radio Resource Location Protocol)
+	\begin{itemize}
+		\item the network can obtain GPS fix or even raw GSM data from the phone
+		\item combine that with the network not needing to authenticate itself
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\subsection{The Baseband}
+
+\begin{frame}{Known GSM security problems}{The Baseband side}
+\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}
+
+\subsection{Observations}
+
+\begin{frame}{Interesting observations}{Learned from implementing the stack}
+While developing OpenBSC, we observed a number of interesting
+\begin{itemize}
+	\item Many phones use their TMSI from the old network when they roam to a new network
+	\item Various phones crash when confronted with incorrect messages.  We didn't even start to intentionally send incorrect messages (!)
+	\item There are tons of obscure options on the GSM spec which no real network uses.  Potential attack vector by using rarely tested code paths.
+\end{itemize}
+\end{frame}
+
+\subsection{GSM Protocol Fuzzing}
+
+\begin{frame}{GSM Protocol Fuzzing}{Theoretical basis}
+How to do GSM protocol fuzzing
+\begin{itemize}
+	\item From the handset to the network
+	\begin{itemize}
+		\item Basically impossible due to closeness of baseband
+		\item However, some incomplete projects working on it
+	\end{itemize}
+	\item From the network side
+	\begin{itemize}
+		\item Easy in case of {\em rogue network} attacks
+		\item Fuzzing target is the GSM stack in the baseband processor
+	\end{itemize}
+	\item As an A-bis man in the middle
+	\begin{itemize}
+		\item Needs access to an A-bis interface of an actual network
+		\item Very attractive, since no encryption and ability to fuzz both network and handset
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\begin{frame}{A-bis injection}{for A-bis over IP}
+How to do inject messages into A-bis over IP?
+\begin{itemize}
+	\item Problem
+	\begin{itemize}
+		\item A-bis/IP uses one TCP connection for OML and RSL messages
+		\item OML initialization is essential for BTS to become operational
+		\item TCP makes insertion of additional messages relatively hard
+	\end{itemize}
+	\item Solution: Build an {\em A-bis injection proxy}
+	\begin{itemize}
+		\item Transparently pass OML and RSL packets between BTS and BSC
+		\item Add additional stateless UDP sockets for injecting messages, one socket each for
+	\end{itemize}
+	\begin{itemize}
+		\item injecting OML/RSL to the network
+		\item injecting OML/RSL to the BTS
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\begin{frame}{A-bis Injection Proxy}{Principle of operation}
+\begin{itemize}
+	\item Proxy needs to be brought between BTS and BSC
+	\item Luckily, A-bis/IP SSL support not always used
+	\item Thus, physical access to the Ethernet link sufficient
+	\item Configure system with two interfaces
+	\begin{itemize}
+		\item BSC-facing interface has IP of BTS
+		\item BTS-facing interface has IP of BSC / default gw
+	\end{itemize}
+	\item BTS will make TCP connection to proxy
+	\item proxy will make independent TCP connection to BSC
+\end{itemize}
+\end{frame}
+
+\begin{frame}{scapy GSM support}{The actual fuzzing}
+How to actually craft the packets for the fuzzing
+\begin{itemize}
+	\item GSM has many, many protocols
+	\item Writing custom code will be a hardcoded special case for each of them
+	\item Solution: Use scapy and implement the GSM protocols as scapy "layers"
+	\begin{itemize}
+		\item IPA protocol header
+		\item RSL protocol layer
+		\item RLL data indication / data request
+		\item GSM 04.08 RR / MM / CC messages
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\begin{frame}{OpenBSC silent calls}{A more elegant fuzzing interface}
+\begin{itemize}
+	\item Injection at the A-bis level has many problems
+	\begin{itemize}
+		\item you can only do it while a call is active
+		\item you simply piggy-back on existing RR connections
+	\end{itemize}
+	\item The OpenBSC {\em silent call} feature can help
+	\begin{itemize}
+		\item we use OpenBSC to establish a RR connection
+		\item in the GSM master/slave model, the phone will not close a connection unless told to do so
+		\item we then send arbitrary data to the phone and receive its responses
+		\item this currently only works from within OpenBSC, but we'll provide UDP injection sockets soon
+	\end{itemize}
+\end{itemize}
+\end{frame}
+
+\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 an a-bis proxy to the network or the phones
+	\end{itemize}
+	\item There is ongoing work for a phone-based tool to fuzz the network
+\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 man has gone before
+\end{itemize}
+\end{frame}
+
+\subsection{Where we go from here}
+
+\begin{frame}{Current Areas of Work / Future plans}
+\begin{itemize}
+	\item Packet data (GPRS/EDGE) support in OpenBSC
+	\begin{itemize}
+		\item GPRS/EDGE is used extensively on modern smartphones
+		\item Enables us to play on IP level with those phones without a heavily filtered operator network
+	\end{itemize}
+	\item UMTS(3G) support in OpenBSC
+	\item Access to MS side layer 1
+	\item Playing with SIM Toolkit from the operator side
+	\item Playing with MMS
+	\item More exploration of RRLP
+\end{itemize}
+\end{frame}
+
+\subsection{Further Reading}
+
+\begin{frame}{Further Reading}
+\begin{itemize}
+	\item http://openbsc.gnumonks.org/
+	\item http://airprobe.org/
+	\item http://openbts.sourceforge.net/
+	\item http://bb.osmocom.org/
+\end{itemize}
+\end{frame}
+
+\end{document}