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diff --git a/2010/openbsc-elce2010/openbsc.tex b/2010/openbsc-elce2010/openbsc.tex new file mode 100644 index 0000000..b387895 --- /dev/null +++ b/2010/openbsc-elce2010/openbsc.tex @@ -0,0 +1,451 @@ +% $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 GSM protocol stacks} + +\subtitle +{OpenBSC, OsmoSGSN, OpenGGSN, OsmocomBB} + +\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[ELCE 2010] % (optional, should be abbreviation of conference name) +{ELCE 2010, October 2010, Cambridge/UK} +% - 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 expert, focus on network protocol security + \item Core developer of Linux packet filter netfilter/iptables + \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 Network planning / deployment / servicing + \item Even 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} + +\begin{frame}{GSM is more than phone calls} +Listening to phone calls is boring... +\begin{itemize} + \item Machine-to-Machine (M2M) communication + \begin{itemize} + \item BMW can unlock/open your car via GSM + \item Alarm systems often report via GSM + \item Smart Metering (Utility companies) + \item GSM-R / European Train Control System + \item Vending machines report that their cash box is full + \item Control if wind-mills supply power into the grid + \item Transaction numbers for electronic banking + \end{itemize} +\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}{The closed GSM industry}{My self-proclaimed mission} +Mission: Bring TCP/IP/Internet security knowledge to GSM +\begin{itemize} + \item Create tools to enable independent/public IT Security community to examine GSM + \item Try to close the estimated 10 year gap between the state of security technology on the Internet vs. GSM networks + \begin{itemize} + \item Industry thinks in terms of {\em walled garden} and {\em phones behaving like specified} + \item No proper incident response strategies! + \item No packet filters, firewalls, intrusion detection on GSM protocol level + \item General public assumes GSM networks are safer than Internet + \end{itemize} +\end{itemize} +\end{frame} + +\begin{frame}{The closed GSM industry}{Areas of interest for Security research} +\begin{itemize} + \item Specification problems + \begin{itemize} + \item Encryption optional, weak and only on the Um interface + \item Lack of mutual authentication + \item Silent calls for pin-pointing a phone + \item RRLP and SUPL to obtain GPS coordinates of phone + \end{itemize} + \item Implementation problems + \begin{itemize} + \item TMSI information leak on network change + \item TLV parsers that have never seen invalid packets + \item Obscure options in spec lead to rarely-tested/used code paths + \end{itemize} + \item Operation problems + \begin{itemize} + \item VLR overflow leading to paging-by-IMSI + \item TMSI re-allocation too infrequent + \item Networks/Cells without frequency hopping + \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 BTS equipment is available, much easier/faster progress + \end{itemize} + \item Result: Started project OpenBSC in 10/2008 +\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 Publicly known attempts (12/2009) + \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 have been successful + \item Result: Started project OsmocomBB in 01/2010 + \end{itemize} +\end{itemize} +\end{frame} + + +\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} + +\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 Frem 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 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 UMTS(3G) support for NodeB and femtocells + \item SS7 / MAP integration + \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.gnumonks.org/} + \item \url{http://openbts.sourceforge.net/} + \item \url{http://airprobe.org/} +\end{itemize} +\end{frame} + +\end{document} |