+\documentclass[handout]{beamer}
+\usetheme{i4}
+\usepackage[utf8]{inputenc}
+\usepackage{tikz}
+\usepackage{multicol}
+\usepackage{listings}
+\lstloadlanguages{lisp}
+
+\usetikzlibrary{svg.path,positioning,intersections}
+\usepgflibrary{shapes.geometric}
+\usepgflibrary{shapes.misc}
+\usepgflibrary{shapes.symbols}
+
+\usepgflibrary{shapes}
+\usetikzlibrary{shapes,decorations,shadows}
+\usetikzlibrary{decorations.pathmorphing}
+\usetikzlibrary{decorations.shapes}
+\usetikzlibrary{fadings}
+\usetikzlibrary{patterns}
+\usetikzlibrary{calc}
+\tikzstyle{netdb}=[anchor=center,color=black,rectangle,draw,minimum
+ size=1em,minimum height=.5em]
+\tikzstyle{client}=[fill=i4gray,rectangle,draw]
+\tikzstyle{chain}=[rectangle,draw,minimum size=1em,minimum height=.5em]
+\tikzstyle{arrow}=[->,thick,draw,shorten <=2pt,shorten >=2pt,]
+\tikzstyle{tunnel}=[fill=gray,shape=ellipse,minimum size=4em,minimum height=1.1em]
+
+\newcommand{\iip}[1]{\textcolor{i4red}{#1}}
+
+\author[Christoph Egger]{{\bf Christoph Egger}, Johannes Schlumberger, Christopher
+ Kruegel, Giovanni Vigna}
+\title{Practical Attacks Against The I2P Network}
+\institute{Friedrich-Alexander University Erlangen-Nuremberg\\
+University of California, Santa Barbara}
+\date{October 25, 2013}
+\begin{document}
+
+\begin{frame}[plain]
+ \vspace{1.5em}
+ \titlepage
+ \begin{center}
+ \includegraphics[width=0.2\paperwidth]{ucsbseal}
+ \hspace{1.5em}
+ \includegraphics[width=0.25\paperwidth]{streifenlogo}
+ \end{center}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Outline}
+ \begin{multicols}{2}
+ \begin{block}{What is I2P?}
+ \begin{itemize}
+ \item Tunnels
+ \item Network Database
+ \item \textcolor{gray}{Floodfill Participation}
+ \item Thread model
+ \end{itemize}
+ \end{block}
+ \begin{block}{Attacks}
+ \begin{itemize}
+ \item \textcolor{gray}{Floodfill Takeover Attack}
+ \item Sybil Attack
+ \item \textcolor{gray}{Eclipse Attack}
+ \item Deanonymization Attack
+ \end{itemize}
+ \end{block}
+ \begin{block}{Evaluation}
+ \begin{itemize}
+ \item \textcolor{gray}{Floodfill Takeover Attack}
+ \item Sybil Attack
+ \item \textcolor{gray}{Eclipse Attack}
+ \item Deanonymization Attack
+ \end{itemize}
+ \end{block}
+ \begin{block}{Conclusions}
+ \begin{itemize}
+ \item Limitations
+ \item I2P Improvements
+ \item \textcolor{gray}{Related Work}
+ \end{itemize}
+ \end{block}
+ \end{multicols}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Introduction I2P}
+ \begin{itemize}\addtolength{\itemsep}{1\baselineskip}
+ \item Solution for anonymous Communication
+ \item Separated from the ``Internet'' -- \emph{Darknet}
+ \item Fully distributed Design
+ \item Based on Onion Routing
+ \item Between 18,000 and 28,000 active users
+ \end{itemize}
+\end{frame}
+\section{I2P}
+\begin{frame}
+ \frametitle{I2P}
+ \begin{multicols}{2}
+ \begin{block}{Router}
+ \begin{itemize}
+ \item Handle Connections
+ \item Provide Name Services
+ \end{itemize}
+ \end{block}
+ \pause
+ \begin{block}{Applications}
+ \begin{itemize}
+ \item Server, Client or P2P Software
+ \item Sockets interface with TCP-like or UDP-like Semantics
+ \end{itemize}
+ \end{block}
+ \pause
+ \begin{figure}
+ \centering
+ \begin{tikzpicture}[scale=1.2]
+ \tikzstyle{every node}=[font=\tiny]
+ \node[minimum width=7em,minimum height=6em,draw=gray](clientpc) at (25mm,9mm) {};
+ \node[above=0mm of clientpc.south] {User's Computer};
+ \node[cloud,drop shadow,fill=white,draw,minimum
+ width=4.5em,minimum height=2.5em](ip) at (22mm,27mm) {I2P};
+ \node[client](client) at (22mm, 18mm) {I2P Router};
+ \node[rectangle,draw,below=0mm of client.south east](app1) {Application};
+ \node[rectangle,draw,below=0mm of app1.south](app2) {Application};
+ \node[rectangle,draw,below=0mm of app2.south](app3) {Application};
+
+ \path[arrow] (app1.west) -| ([xshift=3.5mm]client.south west);
+ \path[arrow] (app2.west) -| ([xshift=2.5mm]client.south west);
+ \path[arrow] (app3.west) -| ([xshift=1.5mm]client.south west);
+ \path[arrow] ([xshift=.5mm]client.north) -- ([xshift=.5mm]ip.south);
+ \path[arrow] ([xshift=-.5mm]ip.south) -- ([xshift=-.5mm]client.north);
+ \end{tikzpicture}
+ \end{figure}
+
+ \end{multicols}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Tunnels}
+ \begin{itemize}
+ \item using onion-routing for anonymity
+ \item unidirectional
+ \item paired for bi-directional communication
+ \end{itemize}\pause
+ \begin{block}{Client Tunnels}
+ \begin{itemize}
+ \item Used for Data Interactions
+ \item Several pro Application
+ \end{itemize}
+ \end{block}
+ \pause
+ \begin{block}{Exploratory Tunnels}
+ \begin{itemize}
+ \item Used for Database interaction
+ \item 2 to 3 per Node
+ \end{itemize}
+ \end{block}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Network Database}
+ \begin{itemize}
+ \item<1-> Kademlia-like DHT based on \texttt{XOR}-distance run on
+ 320 super-nodes
+ \item<2-> \iip{databaseRecord}\\
+ Information named using a hash over their cryptographic Keys
+ \item<3-> \iip{storageLocation}\\
+ Hash over name and today's date
+ \item<4-> \iip{routerInfo}\\
+ Peer information: IP address, Port, Protocol, Keys
+ \item<5-> \iip{leaseSet}\\
+ Service Information: Entry tunnels, Keys
+ \end{itemize}
+ % \begin{multicols}{2}
+ % \begin{block}{\iip{routerInfo}}
+ % \begin{itemize}
+ % \item Peer information: IP address, Port, Protocol, Keys
+ % \end{itemize}
+ % \end{block}
+ % \begin{block}{\iip{leaseSet}}
+ % \begin{itemize}
+ % \item Service Information: Entry tunnels, Keys
+ % \end{itemize}
+ % \end{block}
+ % % \begin{figure}
+ % % \centering
+ % % \begin{tikzpicture}
+ % % \node[draw,rectangle split, rectangle split parts=2] (lease) at (-3em,0) {\iip{leaseSet}\nodepart{second}\tiny{Keys}};
+ % % \node[draw,rectangle split, rectangle split parts=2] (router) at (3em,0) {\iip{routerInfo}\nodepart{second}\tiny{Keys}};
+ % % \node[draw,ellipse] (hashfn1) at (0,-3em) {\tiny{SHA256}};
+ % % \node[draw,rectangle] (hash1) at (0,-5.5em) {\iip{resourceIdentifier}};
+ % % \node[draw,rectangle,right=-0.1mm of hash1.east] (day) {Date};
+
+ % % \node[draw,ellipse] (hashfn1) at (0,-8em) {\tiny{SHA256}};
+ % % \node[draw,rectangle] (resID) at (0,-10.5em) {\iip{storageLocation}};
+ % % \end{tikzpicture}
+ % % \end{figure}
+ % \end{multicols}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Sample Interaction}
+ \begin{figure}
+ \centering
+ \begin{tikzpicture}[scale=1.2]
+ \tikzstyle{every node}=[font=\tiny]
+% netDB
+ \foreach \sector in {%
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9}%
+ {
+ \node[netdb](node\sector) at ({36 * (-\sector + .5)} : 10mm) {\sector};
+ }
+ \node at (0, 0) {netDB};
+% client
+ \node[client](client) at (28mm, 12mm) {Server Router};
+ \node[rectangle,draw,below=0mm of client.south west] {Application};
+ \node[minimum width=7em,minimum height=4em,draw=gray](clientpc) at (25mm,9mm) {};
+ \node[above=0mm of clientpc.south] {Server's System};
+% server
+ \node[client](server) at (-42mm, 12mm) {Client Router};
+ \node[rectangle,draw,below=0mm of server.south east] {Application};
+ \node[minimum width=7em,minimum height=4em,draw=gray](clientpc) at (-38mm,9mm) {};
+ \node[above=0mm of clientpc.south] {Client's System};
+% client client tunnel
+ \node[chain,minimum size=6.5em,minimum height=2em,draw=gray](tunnel) at (16mm,20.5mm) {};
+ \node[above=0mm of tunnel.north] {Server's data tunnel pair};
+% \node[tunnel,minimum width=9.5em] at (16mm, 19mm) {};
+% \node[tunnel,minimum width=9.5em] at (16mm, 22mm) {};
+%
+ \node[chain] (cco1) at (23mm, 19mm) {};
+ \path[arrow] ([xshift=4mm]client.north) |- (cco1.east);
+ \node[chain] (cco2) at (16mm, 19mm) {};
+ \path[arrow] (cco1.west) -- (cco2.east);
+ \node[chain] (cco3) at (9mm, 19mm) {};
+ \path[arrow] (cco2.west) -- (cco3.east);
+ \node[chain] (cci1) at (23mm, 22mm) {};
+ \path[arrow] (cci1.east) -| ([xshift=5mm]client.north);
+ \node[chain] (cci2) at (16mm, 22mm) {};
+ \path[arrow] (cci2.east) -- (cci1.west);
+ \node[chain] (cci3) at (9mm, 22mm) {};
+ \path[arrow] (cci3.east) -- (cci2.west);
+% server client tunnel
+ \node[chain,minimum size=6.5em,minimum height=2em,draw=gray](tunnel) at (-30mm,20.5mm) {};
+ \node[above=0mm of tunnel.north] {Client's data tunnel pair};
+% \node[tunnel,minimum width=9.5em] at (-34mm, 19mm) {};
+% \node[tunnel,minimum width=9.5em] at (-34mm, 22mm) {};
+%
+ \node[chain] (csi1) at (-37mm, 19mm) {};
+ \path[arrow,<-] ([xshift=-4mm]server.north) |- (csi1.west);
+ \node[chain] (csi2) at (-30mm, 19mm) {};
+ \path[arrow,<-] (csi1.east) -- (csi2.west);
+ \node[chain] (csi3) at (-23mm, 19mm) {};
+ \path[arrow,<-] (csi2.east) -- (csi3.west);
+ \node[chain] (cso1) at (-37mm, 22mm) {};
+ \path[arrow,<-] (cso1.west) -| ([xshift=-5mm]server.north);
+ \node[chain] (cso2) at (-30mm, 22mm) {};
+ \path[arrow,<-] (cso2.west) -- (cso1.east);
+ \node[chain] (cso3) at (-23mm, 22mm) {};
+ \path[arrow,<-] (cso3.west) -- (cso2.east);
+% client exploratory tunnel
+ \node[chain,minimum size=4.5em,minimum height=2em,draw=gray](tunnel) at (-32.5mm,-3.5mm) {};
+ \node[below=0mm of tunnel.south,align=center] {Client's exploratory\\tunnel pair};
+% \node[tunnel,minimum width=7.5em] at (-36.5mm, 0mm) {};
+% \node[tunnel,minimum width=7.5em] at (-36.5mm, -3mm) {};
+%
+ \node[chain] (eo1) at (-36mm, -2mm) {};
+ \path[arrow] ([xshift=-4mm]server.south) |- (eo1.west);
+ \node[chain] (ei1) at (-36mm, -5mm) {};
+ \path[arrow,<-] ([xshift=-5mm]server.south) |- (ei1.west);
+ \node[chain] (eo2) at (-29mm, -2mm) {};
+ \path[arrow] (eo1.east) -- (eo2.west);
+ \node[chain] (ei2) at (-29mm, -5mm) {};
+ \path[arrow,<-] (ei1.east) -- (ei2.west);
+% service lookup
+ \draw[arrow,bend right=20,dashdotted] (eo2.east) to node[above=.8em,align=center] {service\\lookup} (node4.west);
+ \draw[arrow,bend right=10,<-,dashdotted] (ei2.east) to node {} ([yshift=-1mm]node4.west);
+% data link
+ \draw[arrow,bend left=15,dashdotted] (cco3.west) to node {} (csi3.east);
+ \draw[arrow,bend right=15,dashdotted] (cci3.west) to node {} (cso3.east);
+ \node at (-9mm,20.5mm) {Data connection};
+ \end{tikzpicture}
+ \end{figure}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Thread Model}
+ \begin{itemize}\addtolength{\itemsep}{1\baselineskip}
+ \item Implicitly specified in terms of attacks considered
+ \item Only allows local adversaries: No global view about traffic
+ passing through the network
+ \item Only allows limited number of malicious nodes -- around 20\,\%
+ of \iip{netDB} super-nodes and 20\,\% of total nodes
+ \item Secure cryptographic primitives
+ \end{itemize}
+\end{frame}
+
+\section{Attacks}
+\begin{frame}
+ \frametitle{Sybil Attack}
+ \begin{block}{Definition}
+ In a Sybil Attack, the adversary utilizes multiple identities to
+ break assumptions about the system
+ \end{block}\pause
+ \begin{block}{Goal}
+ Gaining control over parts of the keyspace in the \iip{netDB} with
+ limited resources
+ \end{block}\pause
+ \begin{block}{Challenge}
+ Active identities require considerable resources to be useful
+ \end{block}\pause
+ \begin{block}{Solution}
+ Compute a large pool of identities and only activate the relevant ones
+ \end{block}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Deanonymizing Users}
+ \begin{block}{Goal}
+ Given an user Alice and a resource R, we want to confirm or refute
+ Alice using R with high probability.
+ \end{block}\pause
+ \begin{block}{Vulnerability}
+ \begin{itemize}
+ \item<2-> Nodes store their \iip{routerInfo} directly in the \iip{netDB}
+ \item<3-> Nodes verify the storage 20 seconds later using one of their
+ \iip{exploratory Tunnels}
+ \item<4-> Nodes use the same \iip{exploratory Tunnel} again for
+ resource lookups
+ \end{itemize}
+ \end{block}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Deanonymizing Users}
+ \begin{figure}
+ \centering
+\begin{tikzpicture}[scale=1.4,font=\tiny]
+% netDB
+ \foreach \sector in {%
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9}%
+ {
+ \node[netdb](node\sector) at ({36 * (-\sector + .5)} : 12mm) {\sector};
+ }
+ \node at (0, 0) {netDB};
+% client
+ \node[client](client) at (-45mm, 12mm) {Client};
+% store
+ \draw[arrow,bend left=5,dashdotted] (client.north east) to node[above] {store} (node7.north west);
+ \draw[arrow,<-,bend left=5,dashdotted] (client.east) to node {} (node7.west);
+% flood
+ \draw[arrow,draw,bend right=15] (node7.south east) to node {} (node8.south west);
+ \draw[arrow,draw,bend right=15] (node7.south east) to node[below] {replication} (node9.west);
+ \draw[arrow,draw,bend left=15] (node7.south east) to node {} (node6.north east);
+% tunnels
+ \node[chain,minimum size=6em,minimum height=3.5em,draw=gray](tunnel) at (-35mm,-2.5mm) {};
+ \node[below=2mm of tunnel.south] {exploratory tunnel pair};
+% \node[tunnel] at (-35mm, 0mm) {};
+ \node[chain] (ol) at (-40mm, 0mm) {};
+ \node[chain] (oe) at (-30mm, 0mm) {};
+% \node[tunnel] at (-35mm, -5mm) {};
+ \node[chain] (il) at (-40mm, -5mm) {};
+ \node[chain] (ie) at (-30mm, -5mm) {};
+ \path[arrow] ([xshift=-1mm]client.south) |- (ol.west);
+ \path[arrow,<-] ([xshift=-2mm]client.south) |- (il.west);
+ \path[arrow] (ol.east) -- (oe.west);
+ \path[arrow,<-] (il.east) -- (ie.west);
+% verify
+ \draw[arrow,bend left=5,dashdotted] (oe.north east) to node[above] {verify} ([yshift=1mm]node6.west);
+ \draw[arrow,bend left=15,<-,dashdotted] (ie.north east) to node {} (node6.west);
+%lookup
+ \draw[arrow,bend right=15,dashdotted] (oe.south east) to node[above] {lookup} (node4.west);
+ \draw[arrow,bend right=5,<-,dashdotted] (ie.south east) to node {} ([yshift=-1mm]node4.west);
+\end{tikzpicture}
+\end{figure}
+\end{frame}
+
+\section{Evaluation}
+\begin{frame}
+ \frametitle{Sybil Attack}
+ \begin{block}{Generating identities}
+ \begin{itemize}
+ \item Building a Database of 50,000 identities takes around 30
+ minutes on 12-core Xeon server
+ \item 156 nodes on average between two adjacent database nodes
+ \item All identities available to all malicious nodes
+ \end{itemize}
+ \end{block}\pause
+ \begin{block}{Using identities}
+ \begin{itemize}
+ \item Malicious nodes can calculate the correct identities and
+ change identity at any time
+ \item Nodes coordinate to avoid duplicate identities
+ \end{itemize}
+ \end{block}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Deanonyizing Attack}
+ \begin{block}{Setup}
+ \begin{itemize}
+ \item 20 attacking nodes in Santa Barbara
+ \begin{itemize}
+ \item 10 nodes capturing resource lookups
+ \item 10 nodes performing timing attack on \iip{routerInfo} storage
+ \end{itemize}
+ \item 6 monitoring nodes: 3 in Erlangen, 3 in Santa Barbara
+ \end{itemize}
+ \end{block}\pause
+ \begin{block}{Results}
+ \begin{itemize}
+ \item 60\,\% of potentially observable links detected
+ \item 52\,\% of attributed hits correct
+ \item Working equally well for geographically remote Hosts
+ \end{itemize}
+ \end{block}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Deanonymizing Users}
+ \begin{figure}
+ \centering
+\begin{tikzpicture}[scale=1.4,font=\tiny]
+% netDB
+ \foreach \sector in {%
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9}%
+ {
+ \node[netdb](node\sector) at ({36 * (-\sector + .5)} : 12mm) {\sector};
+ }
+ \node at (0, 0) {netDB};
+% client
+ \node[client](client) at (-45mm, 12mm) {Client};
+% store
+ \draw[arrow,bend left=5,dashdotted] (client.north east) to node[above] {store} (node7.north west);
+ \draw[arrow,<-,bend left=5,dashdotted] (client.east) to node {} (node7.west);
+% flood
+ \draw[arrow,draw,bend right=15] (node7.south east) to node {} (node8.south west);
+ \draw[arrow,draw,bend right=15] (node7.south east) to node[below] {replication} (node9.west);
+ \draw[arrow,draw,bend left=15] (node7.south east) to node {} (node6.north east);
+% tunnels
+ \node[chain,minimum size=6em,minimum height=3.5em,draw=gray](tunnel) at (-35mm,-2.5mm) {};
+ \node[below=2mm of tunnel.south] {exploratory tunnel pair};
+% \node[tunnel] at (-35mm, 0mm) {};
+ \node[chain] (ol) at (-40mm, 0mm) {};
+ \node[chain] (oe) at (-30mm, 0mm) {};
+% \node[tunnel] at (-35mm, -5mm) {};
+ \node[chain] (il) at (-40mm, -5mm) {};
+ \node[chain] (ie) at (-30mm, -5mm) {};
+ \path[arrow] ([xshift=-1mm]client.south) |- (ol.west);
+ \path[arrow,<-] ([xshift=-2mm]client.south) |- (il.west);
+ \path[arrow] (ol.east) -- (oe.west);
+ \path[arrow,<-] (il.east) -- (ie.west);
+% verify
+ \draw[arrow,bend left=5,dashdotted] (oe.north east) to node[above] {verify} ([yshift=1mm]node6.west);
+ \draw[arrow,bend left=15,<-,dashdotted] (ie.north east) to node {} (node6.west);
+%lookup
+ \draw[arrow,bend right=15,dashdotted] (oe.south east) to node[above] {lookup} (node4.west);
+ \draw[arrow,bend right=5,<-,dashdotted] (ie.south east) to node {} ([yshift=-1mm]node4.west);
+\end{tikzpicture}
+\end{figure}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Results for multiple Hits}
+ \small{
+ $N=144$, Number of time slices\\
+ $q=0.001$, 7\,\% of total nodes accessing the resource once a day\\
+ $x=0.52\cdot p + 0.48\cdot q$ \\
+ $P(k~hits) = {N \choose k} x^k \cdot (1-x)^{N-k}$}
+ \begin{figure}
+ \centering
+ \includegraphics[width=.7\textwidth]{graph}
+ \end{figure}
+\end{frame}
+
+\section{Conclusions}
+
+\begin{frame}
+ \frametitle{Limitations}
+ \begin{itemize}\addtolength{\itemsep}{1\baselineskip}
+ \item Only works reliable for longer/repeated resource access
+ \item Less reliable for popular resources
+ \item Needs extra resources per tracked user and per resource
+ \end{itemize}
+\end{frame}
+
+\begin{frame}
+ \frametitle{I2P Improvements}
+ \begin{itemize}\addtolength{\itemsep}{1\baselineskip}
+ \item Limiting \iip{netDB} nodes per IPv4 network
+ \item Ignoring new \iip{netDB} nodes
+ \item Removing storage verification
+ \item Randomizing the time delta
+ \item Expiring tunnels after storage verification
+ \end{itemize}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Bibliography}
+ \nocite{Mittal:2012}
+ \nocite{Timpanaro:2011}
+ \nocite{Herrmann:2011}
+ \nocite{Douceur:2002}
+ \nocite{Dingledine:2004}
+ \nocite{Evans:2011}
+ \bibliographystyle{plain}
+ \tiny{\bibliography{../i2p}}
+\end{frame}
+
+\end{document}
+
+%%% Local Variables:
+%%% mode: latex
+%%% TeX-master: t
+%%% TeX-PDF-mode: t
+%%% End:
\ No newline at end of file
projects / talk / attack-i2p-raid2013.git / commitdiff