Author: linus Date: 2012-05-24 20:34:41 +0000 (Thu, 24 May 2012) New Revision: 25660
Added: projects/presentations/2012-05-24-Swedish-police-IT-forensics.pdf projects/presentations/2012-05-24-Swedish-police-IT-forensics.tex projects/presentations/images/NORDUnet-New-Logo-Final-Small.jpg projects/presentations/images/StenographyOriginal.png projects/presentations/images/StenographyRecovered.png projects/presentations/images/cryptography-trafficanalysis.png projects/presentations/images/direct-users-off-2010-06-01-on-300-2011-05-01-eg.png projects/presentations/images/networksize-2009-01-01-300-2012-05-23.png Log: Add 2012-05-24-Swedish-police-IT-forensics.
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Added: projects/presentations/2012-05-24-Swedish-police-IT-forensics.tex =================================================================== --- projects/presentations/2012-05-24-Swedish-police-IT-forensics.tex (rev 0) +++ projects/presentations/2012-05-24-Swedish-police-IT-forensics.tex 2012-05-24 20:34:41 UTC (rev 25660) @@ -0,0 +1,415 @@ +% Copyright 2012 by NORDUnet A/S info@nordu.net +% Author: Linus Nordberg linus@nordu.net +% +% This presentation is based on the conference-ornate-20min template +% by Till Tantau tantau@users.sourceforge.net. You may redistribute +% and/or modify it under the terms of the GNU Public License, version +% 2. +% +% To produce a PDF from this document, do something like +% +% pdflatex FILE.tex +% +% You might want to have packages like tetex, latex-beamer and +% ghostscript installed. + +\documentclass{beamer} +\mode<presentation> +{ + \usetheme{Warsaw} + \setbeamercovered{transparent} +} +\usepackage[english]{babel} +\usepackage[latin1]{inputenc} +\usepackage{times} +\usepackage[T1]{fontenc} +\usepackage{url} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\title{Tor f�r IT-forensiker} +\subtitle{} +\author{Linus Nordberg, NORDUnet} +\date[2012-05-24]{IT-forensiska seminariet 2012} +\pgfdeclareimage[height=0.3cm]{ndn-logo}{../images/NORDUnet-New-Logo-Final-Small} +\logo{\pgfuseimage{ndn-logo}} +% +\AtBeginSection[] +{ + \begin{frame}<beamer>{Inneh�ll} + \tableofcontents[currentsection,currentsubsection] + \end{frame} +} + +% Enable this to make items appear one at a time. +%\beamerdefaultoverlayspecification{<+->} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\begin{document} +\begin{frame} + \titlepage +\end{frame} +%\begin{frame}{outline} +% \tableofcontents +%\end{frame} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\section{Presentation} +\begin{frame}{Presentation} +\begin{itemize} +\item Yrke programmerare +\pause \item Anst�lld av NORDUnet +\pause \item Tor-relaterat arbete inkluderar f�rel�sningar, drift av + m�ttj�nster och rel�n, utveckling (Tor p� IPv6) +\pause \item Kontakt linus@nordu.net 0x23291265 \ + \tiny 8C4C D511 095E 982E B0EF BFA2 1E8B F349 2329 1265 +\end{itemize} +\end{frame} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\section{Vad �r Tor} + +\begin{frame}{Ett protokoll och ett program} +\begin{itemize} +\item Ett n�tverksprotokoll +\pause \item Ett program -- fri programvara, BSD-licensierad +\pause \item �ppna epostlistor, k�llkods-arkiv med specifikationer, + f�r�ndringsf�rslag och kod, ``bug tracker'', chatrum +\pause \item Teknik och urpsrunglig kod fr�n NRL (U.S. Naval Research + Laboratory) +\pause ==> ``onion routing'' 1996 +\pause ==> Tor 2002 +\end{itemize} +\end{frame} + +\begin{frame}{Tre funktioner} +\begin{itemize} +\item Anonym och skyddad �tkomst till internet +\pause \item Kringg� blockering +\pause \item Anonym och skyddad publicering +\end{itemize} +\end{frame} + +\begin{frame}{Ett ekosystem av applikationer} +\begin{itemize} +\item Browsern Aurora -- Firefox + Torbutton +\pause \item Vidalia -- en kontrollpanel +\pause \item Metrics -- analysverktyg och information om n�tet +\pause \item TBB (Tor Browser Bundle) -- Vidalia + FF + Torbutton +\pause \item Tails -- en live-CD/USB med TBB +\pause \item Orbot -- Tor f�r Android +\end{itemize} +\end{frame} + +\begin{frame}{Vidalia -- en kontrollpanel} +\parbox{3.5cm}{\sloppy \includegraphics[width=3cm]{../images/vidalia-control-panel}} +\parbox{7cm}{\sloppy \includegraphics[width=7cm]{../images/vidalia-network-map}} +\end{frame} + +\begin{frame}{En ``non-profit org''} +\parbox{4.5cm}{\sloppy +\setbeamercolor{background}[\includegraphics[width=3.8cm]{../images/2009-tor-logo}} +\parbox{6cm}{\sloppy +\begin{itemize} +\item 501(c)(3) -- non-profit (ideell org) f�r forskning och + utveckling av teknologi f�r anonymitet och skyddande av personlig + integritet p� n�tet (2006) +\item Historia -- NRL, Electronic Frontier Foundation (EFF) +\end{itemize} +} +\end{frame} + +\begin{frame}{En ``non-profit org''} +\parbox{4.5cm}{\sloppy +\setbeamercolor{background}[\includegraphics[width=3.8cm]{../images/2009-tor-logo}} +\parbox{6cm}{\sloppy +\begin{itemize} +\item Finansiering -- BBG, Sida, Internews, NSF, NLnet, NRL, + individuals, Google, HRW (EFF, DARPa, Bell) +\item Tor Project Inc (2011) -- Kommersialisering f�r att hitta + privata sponsorer +\end{itemize} +} +\end{frame} + +\begin{frame}{Community} +\begin{itemize} +\item{Forskare} \ Drexel, Univ of Waterloo, Georgia Tech, Princeton, + Boston University, University College London, Univ of Minnesota, + MIT, National Science Foundation, Naval Research Labs, Cambridge + (UK), Bamberg (Tyskland) \pause +\item{Programutvecklare} \ Ca 5 heltid + ca 20 deltid (betalda och + obetalda) + 6 GSOC-studenter + m�nga tillf�lliga bugrapport�rer, + mindre patchar mm. +\end{itemize} +\end{frame} + +\begin{frame}{Community} +\begin{itemize} +\item{Rel�-operat�rer} \ 2000-3000, framf�r allt i USA och Europa \pause +\item{Anv�ndare} \ Ca 400,000 dagliga anv�ndare \ + \tiny \url{https://metrics.torproject.org/users.html%7D +\end{itemize} +\end{frame} + +\begin{frame}{Infrastruktur} +Ett frivillign�tverk best�ende av ca 3000 rel�n +\begin{overlayarea}{8cm}{5cm} +\begin{center} +\includegraphics[scale=0.35]{../images/networksize-2009-01-01-300-2012-05-23} +\end{center} +\end{overlayarea} +\end{frame} + +%%%% +\section{Vad �r anonymitet} + +\begin{frame}{Enbart kryptering ger inte anonymitet} +\parbox{6cm}{\sloppy +\setbeamercolor{background}[\includegraphics[width=5.9cm]{../images/cryptography-trafficanalysis}} +\parbox{4cm}{\sloppy +\begin{itemize} +\item Krypto skyddar data vid �verf�ring \pause +\item Man kan fortfarande se vem som pratar med vem, hur ofta och hur + mycket +\end{itemize} +} +\end{frame} + +\begin{frame}{Steganografi ger inte anonymitet} +\parbox{4cm}{\sloppy +\includegraphics[scale=0.40]{../images/StenographyOriginal} \ +\includegraphics[scale=0.40]{../images/StenographyRecovered} +} +\parbox{5.5cm}{\sloppy +\begin{itemize} +\item Stego d�ljer datat \pause +\item Man kan fortfarande se att Alice pratar med n�gon, hur ofta och + hur mycket +\end{itemize} +} +\end{frame} + +\begin{frame}{�nsket�nkande ger inte anonymitet} +\begin{itemize} +\item ``Du kan inte bevisa att det var jag'' +\item ``Lova att inte titta'' +\item ``Lova att inte lagra'' +\item ``Lova att inte ber�tta f�r n�gon'' +\end{itemize} +\end{frame} + +\begin{frame}{�nsket�nkande ger inte anonymitet} +\begin{itemize} +\item Bevis -- Beh�vs inte, statistisk analys r�cker l�ngt \pause +\item L�ften -- Kommer de h�llas? Finns incitament och kompetens? + Databaser l�cker. \pause +\item ==> ``Privacy by design, not privacy by policy'' +\end{itemize} +\end{frame} + +\begin{frame}{Blanda sig med m�ngden} +\begin{itemize} +\item Anv�ndaren m�ste g�mmas i en massa \pause +\item Ett system f�r detta m�ste f� anv�ndaren att se ut som alla + andra \pause +\item D�lja vem som pratar med vem \pause +\item �ven f�r operat�rer av systemet +\end{itemize} +\end{frame} + +\begin{frame}{Vem anv�nder Tor} +\begin{itemize} +\item{Vanliga m�nniskor} \ Reklamn�tverk, s�kmotorer, kringg� censur. \pause +\item{Polisen} \ Unders�kning utan uniformen p�, skydd av privatliv. \pause +\item{N�taktivister} \ Blogga, personlig s�kerhet, �tkomst till + blockerade sidor. \pause +\item{Milit�ren} \ I f�lt, separera privatliv och tj�nstg�ring. \pause +\item{Personer med skyddad identitet} \ Offer f�r kvinnofridsbrott + beh�ver ocks� internet, t.ex. f�r kontakt med andra. +\end{itemize} +\end{frame} + +%\begin{frame}{Egypten} +%\includegraphics[height=6cm]{../images/direct-users-off-2010-06-01-on-300-2011-05-01-eg} +%\end{frame} + +%%%% +\section{Hur fungerar Tor} + +\begin{frame}{Enhopps-proxy} +\begin{overlayarea}{9cm}{6cm} +\only<1>{\includegraphics[height=6cm]{../images/single_hop_relay}} +\only<2>{\includegraphics[height=6cm]{../images/evil_single_hop_relay}} +\only<3>{\includegraphics[height=6cm]{../images/data_snooping_single_hop_relay}} +\end{overlayarea} +\end{frame} + +\begin{frame}{Tor g�r tre hopp} +\begin{center} +\begin{overlayarea}{8cm}{5.5cm} +\only<1>{\includegraphics[height=5.3cm]{../images/tor-network}} +\only<2>{\includegraphics[height=5.3cm]{../images/tor-safe-selection}} +\only<3>{\includegraphics[height=5.3cm]{../images/tor-safe-path}} +\end{overlayarea} +\flushright +\tiny Diagram: Robert Watson +\end{center} +\end{frame} + +\begin{frame}{Tor g�r tre hopp} +\begin{itemize} +\item Ett komprometterat f�rsta hopp kan se att Alice pratar men inte + med vem \pause +\item Ett komprometterat sista hopp kan se att n�gon pratar med Bob + men inte vem +\end{itemize} +\end{frame} + +\begin{frame}{Tre lager av kryptering} +\begin{itemize} +\item Alice v�ljer tre rel�n ur n�tverkslistan (konsensus) \pause +\item Exit-policyn hos sista rel�t till�ter uppkoppling till Bobs + adress och port \pause +\item Alice f�rhandlar fram nycklar med det f�rsta rel�t (128-bits + AES-CTR mha D-H) och s�tter upp en ``circuit'' dit (CREATE/CREATED) + \pause +\item Hoppar vidare till andra rel�t (EXTEND/EXTENDED --> + CREATE/CREATED) \pause +\item Hoppar vidare till tredje och sista rel�t \pause +\item Sista rel�t s�tter upp TCP-koppel till Bobs tj�nst +\end{itemize} +\end{frame} + +\begin{frame}{Tre lager av kryptering} +\begin{center} +\begin{overlayarea}{8cm}{5.5cm} +\includegraphics[width=7cm]{../images/tor-keys1} +\end{overlayarea} +\end{center} +\end{frame} + +\begin{frame}{Kryptering av transportlager} +\begin{itemize} +\item TLS/SSLv3 f�r kryptering och autenticering \pause +\item Tre versioner av handskakning f�rhandlar fram version \pause +\item v2 och v3: NETINFO, VERSIONS \pause +\item v3: CERTS AUTH_CHALLLENGE, AUTHENTICATE +\end{itemize} +\end{frame} + +\begin{frame}{Nycklar och certifikat} +\begin{itemize} +\item Varje rel� har en ``long term identity key'' som signerar + TLS-cert och ``network documents (``server descriptors'' och + konsensus) \pause +\item En ``medium term onion key'' f�r dekryptering av EXTEND-celler \pause +\item En ``short term connection key'' f�r TLS-koppel +\end{itemize} +\end{frame} + +\begin{frame}{Server descriptors} +\begin{itemize} +\item Ett rel�s beskrivning av sig sj�lvt \pause +\item Inneh�ller nickname, annonserad kapacitet, timestamp, publik del + av identity key, IP-adress och port(ar), onion key (publika delen), + exit policy, family, m.m. \pause +\item Signeras med identity key \pause +\item Laddas upp till ``directory authorities'' \pause +\item Bakas ihop till ``konsensus'' -- listan �ver de rel�er som utg�r + Tor-n�tverket f�r en timme fram�ver +\end{itemize} +\end{frame} + +\begin{frame}{Directory authorities} +\begin{itemize} +\item �tta stycken i fem l�nder (plus en f�r bryggor) \pause +\item R�star fram en s.k. konsensus varje timme \pause +\item Konsensus utg�r n�tverkskartan \pause +\item Signeras med ``long term key'' \pause +\item Klienter laddar ner konsensus och v�ljer rel�n ur denna f�r att + bygga circuits \pause +\item Listan p� directory authorities och deras long term keys finns + inkompilerad i klienten (och rel�n) +\end{itemize} +\end{frame} + +\begin{frame}{Bryggor} +\begin{itemize} +\item Bryggor �r ``semipublika'' rel�n \pause +\item Fungerar som bryggor mellan internet och Tor-n�tet f�r anv�ndare + som inte kan n� publika rel�n p.g.a. blockering \pause +\item Tor-n�tet har en ``bridge authority'' dit en brygga kan ladda + upp sin deskriptor \pause +\item Bryggor sprids sedan av Tor-projektet via e-post, web, IM, + kontakter\pause +\item Privata bryggor laddar inte upp deskriptorer utan operat�ren + sprider sj�lv bryggans address och port +\end{itemize} +\end{frame} + +\begin{frame}{Hidden services} +\begin{itemize} +\item 2004, f�r anti-DoS och fysisk s�kerhet \pause +\item Lasse �verlier, FFI (Forsvarets forskningsinstitutt) +\end{itemize} +\end{frame} + +\begin{frame}{Svagheter} +\begin{itemize} +\item End-to-end timing correlation \pause +\item Applikationslagret -- browsers l�cker som s�ll \pause +\item Bittorent l�cker -- se bl.a. papper fr�n NRIA 2010 \ + \tiny \url{https://blog.torproject.org/blog/bittorrent-over-tor-isnt-good-idea%7D +\end{itemize} +\end{frame} + +%%%% +\section{Verktyg} + +\begin{frame}{Metrics -- m�tdata, statistik, grafer} +\begin{itemize} +\item N�tstatus -- konsensus, s�ka p� rel�er \pause +\item Grafer -- statistik f�r n�t, anv�ndare, nedladdningar, prestanda \pause +\item M�tdata som ligger till grund f�r graferna \pause +\item Forskningspapper och tekniska rapporter \pause +\item Verktyg -- TorDNSEL och ExoneraTor +\end{itemize} +\end{frame} + +\begin{frame}{TorDNSEL} +\begin{itemize} +\item DNS-baserad lista av exitrel�n \pause +\item Svarar snabbt p� fr�gan ``�r den h�r IP-addressen ett exitrel� + just nu?'' \pause +\item Anv�nds i applikationer f�r att t.ex. kr�va autenticering eller + en CAPTCHA \pause +\item Anv�nd Tor-projektets tj�nst eller k�r den sj�lv +\end{itemize} +\end{frame} + +\begin{frame}{ExoneraTor} +\begin{itemize} +\item Svarar p� fr�gan ``Agerade den h�r IP-adressen och porten + Tor-exitrel� vid den h�r tidpunkten?'' \pause +\item Ladda ner verktyg och databas och st�ll lokala fr�gor \pause +\item Tj�nst tillhandah�llen av Tor-projektet: + \small \url{https://metrics.torproject.org/exonerator.html%7D +\end{itemize} +\end{frame} + +%%%% +\section{Avslutning} +\begin{frame}{K�llor, tillerk�nnanden} +\begin{itemize} +\item Krypto skyddar data vid �verf�ring (Alice, Bob och ondskan): Ilja Hallberg +\item Tr�det med katten i: GFDL + \tiny \url{https://commons.wikimedia.org/wiki/GNU_Free_Documentation_License%7D +\item Katten (utan tr�d): GFDL + \tiny \url{https://commons.wikimedia.org/wiki/GNU_Free_Documentation_License%7D +\end{itemize} +\end{frame} + +\begin{frame}{Fr�gor} +\begin{center} +Fr�gor? +\end{center} +\end{frame} + +%%%% +\end{document}
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