| author | cu |
| Wed, 18 Oct 2017 14:38:25 +0100 | |
| changeset 552 | c1e9a435e16f |
| parent 518 | e1fcfba63a31 |
| child 556 | e6e87d5839c0 |
| permissions | -rw-r--r-- |
| 495 | 1 |
\PassOptionsToPackage{bookmarks=false}{hyperref}
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\usepackage{../slides}
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\usepackage{../graphics}
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\setmonofont[Scale=.88]{Consolas}
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\hfuzz=220pt |
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% beamer stuff |
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\newcommand{\bl}[1]{\textcolor{blue}{#1}}
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\renewcommand{\slidecaption}{SEN 05, King's College London}
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\begin{document}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[t]
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\frametitle{%
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\begin{tabular}{@ {}c@ {}}
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\\ |
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\LARGE Security Engineering (6)\\[-3mm] |
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\end{tabular}}\bigskip\bigskip\bigskip
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\normalsize |
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\begin{center}
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\begin{tabular}{ll}
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Email: & christian.urban at kcl.ac.uk\\ |
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Office: & N7.07 (North Wing, Bush House)\\ |
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Slides: & KEATS (also homework is there)\\ |
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\end{tabular}
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\end{center}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Topical Slide}
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\begin{itemize}
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\item DoS attack agains some US webpages (hijacked IoT devives, like |
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cameras,\ldots) |
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\item funny cow attack (privilege escalation attack) |
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\end{itemize}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Protocols}
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\begin{center}
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\includegraphics[scale=0.11]{../pics/keyfob.jpg}
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\quad |
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\includegraphics[scale=0.3025]{../pics/startstop.jpg}
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\end{center}
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\begin{itemize}
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\item Other examples: Wifi, Http-request, TCP-request, |
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card readers, RFID (passports)\ldots\medskip\pause |
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\item The point is that we cannot control the network: An attacker |
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can install a packet sniffer, inject packets, modify packets, |
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replay messages\ldots{}fake pretty much everything.
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\end{itemize}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Keyless Car Transponders}
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\begin{center}
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\includegraphics[scale=0.1]{../pics/keyfob.jpg}
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\quad |
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\includegraphics[scale=0.27]{../pics/startstop.jpg}
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\end{center}
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\begin{itemize}
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\item There are two security mechanisms: one remote central |
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locking system and one passive RFID tag (engine immobiliser). |
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\item How can I get in? How can thieves be kept out? |
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How to avoid MITM attacks? |
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\end{itemize}\medskip
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\footnotesize |
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\hfill Papers: Gone in 360 Seconds: Hijacking with Hitag2,\\ |
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\hfill Dismantling Megamos Crypto: Wirelessly Lockpicking\\ |
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\hfill a Vehicle Immobilizer |
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Public-Key Infrastructure}
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\begin{itemize}
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\item the idea is to have a certificate authority (CA) |
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\item you go to the CA to identify yourself |
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\item CA: ``I, the CA, have verified that public key \bl{$P^{pub}_{Bob}$} belongs to Bob''\bigskip
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\item CA must be trusted by everybody |
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\item What happens if CA issues a false certificate? Who pays in case of loss? (VeriSign |
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explicitly limits liability to \$100.) |
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\end{itemize}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Man-in-the-Middle}
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``Normal'' protocol run:\bigskip |
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\begin{itemize}
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\item \bl{$A$} sends public key to \bl{$B$}
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\item \bl{$B$} sends public key to \bl{$A$}
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\item \bl{$A$} sends message encrypted with \bl{$B$}'s public key, \bl{$B$} decrypts it
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with its private key |
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\item \bl{$B$} sends message encrypted with \bl{$A$}'s public key, \bl{$A$} decrypts it
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with its private key |
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\end{itemize}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Man-in-the-Middle}
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Attack: |
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\begin{itemize}
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\item \bl{$A$} sends public key to \bl{$B$} --- \bl{$C$} intercepts this message and send his own public key
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\item \bl{$B$} sends public key to \bl{$A$} --- \bl{$C$} intercepts this message and send his own public key
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\item \bl{$A$} sends message encrypted with \bl{$C$}'s public key, \bl{$C$} decrypts it
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with its private key, re-encrypts with \bl{$B$}'s public key
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\item similar for other direction |
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\end{itemize}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Man-in-the-Middle}
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Potential Prevention? |
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\begin{itemize}
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\item \bl{$A$} sends public key to \bl{$B$}
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\item \bl{$B$} sends public key to \bl{$A$}
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\item \bl{$A$} encrypts message with \bl{$B$}'s public key, send's {\bf half} of the message
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\item \bl{$B$} encrypts message with \bl{$A$}'s public key, send's {\bf half} of the message
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\item \bl{$A$} sends other half, \bl{$B$} can now decrypt entire message
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\item \bl{$B$} sends other half, \bl{$A$} can now decrypt entire message
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\end{itemize}\pause
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%\bl{$C$} would have to invent a totally new message
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\alert{Under which circumstances does this protocol prevent
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MiM-attacks, or does it?} |
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Car Transponder (HiTag2)}
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\begin{enumerate}
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\item \bl{$C$} generates a random number \bl{$N$}
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\item \bl{$C$} calculates \bl{$(F,G) = \{N\}_K$}
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\item \bl{$C \to T$}: \bl{$N, F$}
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\item \bl{$T$} calculates \bl{$(F',G') = \{N\}_K$}
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\item \bl{$T$} checks that \bl{$F = F'$}
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\item \bl{$T \to C$}: \bl{$N, G'$}
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\item \bl{$C$} checks that \bl{$G = G'$}
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\end{enumerate}\pause
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\small |
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This process means that the transponder believes the car knows |
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the key \bl{$K$}, and the car believes the transponder knows
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the key \bl{$K$}. They have authenticated themselves
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to each other, or have they? |
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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A Man-in-the-middle attack in real life: |
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\begin{itemize}
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\item the card only says yes to the terminal if the PIN is correct |
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\item trick the card in thinking transaction is verified by signature |
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\item trick the terminal in thinking the transaction was verified by PIN |
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\end{itemize}
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\begin{minipage}{1.1\textwidth}
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\begin{center}
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\mbox{}\hspace{-6mm}\includegraphics[scale=0.5]{../pics/chip-attack.png}
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\includegraphics[scale=0.3]{../pics/chipnpinflaw.png}
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\end{center}
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\end{minipage}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Problems with EMV}
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\begin{itemize}
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\item it is a wrapper for many protocols |
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\item specification by consensus (resulted unmanageable complexity) |
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\item its specification is 700 pages in English plus 2000+ pages for testing, additionally some |
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further parts are secret |
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\item other attacks have been found |
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\end{itemize}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Protocols are Difficult}
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\begin{itemize}
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\item even the systems designed by experts regularly fail\medskip |
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\item the one who can fix a system should also be liable for the losses\medskip |
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\item cryptography is often not the problem\bigskip\bigskip |
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\end{itemize}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{A Simple PK Protocol}
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\begin{center}
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\begin{tabular}{ll@{\hspace{2mm}}l}
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1. & \bl{$A \to B :$} & \bl{$K^{pub}_A$}\smallskip\\
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2. & \bl{$B \to A :$} & \bl{$K^{pub}_B$}\smallskip\\
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3. & \bl{$A \to B :$} & \bl{$\{A,m\}_{K^{pub}_B}$}\smallskip\\
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4. & \bl{$B \to A :$} & \bl{$\{B,m'\}_{K^{pub}_A}$}
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\end{tabular}
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\end{center}\pause\bigskip
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unfortunately there is a simple man-in-the- middle-attack |
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{A MITM Attack}
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\begin{center}
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\begin{tabular}{ll@{\hspace{2mm}}l}
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1. & \bl{$A \to E :$} & \bl{$K^{pub}_A$}\smallskip\\
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2. & \bl{$E \to B :$} & \bl{$K^{pub}_E$}\smallskip\\
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3. & \bl{$B \to E :$} & \bl{$K^{pub}_B$}\smallskip\\
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4. & \bl{$E \to A :$} & \bl{$K^{pub}_E$}\smallskip\\
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5. & \bl{$A \to E :$} & \bl{$\{A,m\}_{K^{pub}_E}$}\smallskip\\
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6. & \bl{$E \to B :$} & \bl{$\{E,m\}_{K^{pub}_B}$}\smallskip\\
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7. & \bl{$B \to E :$} & \bl{$\{B,m'\}_{K^{pub}_E}$}\smallskip\\
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8. & \bl{$E \to A :$} & \bl{$\{E,m'\}_{K^{pub}_A}$}
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\end{tabular}
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\end{center}\pause\medskip
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and \bl{$A$} and \bl{$B$} have no chance to detect it
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Interlock Protocol}
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The interlock protocol (``best bet'' against MITM): |
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\begin{center}
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\begin{tabular}{ll@{\hspace{2mm}}l}
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1. & \bl{$A \to B :$} & \bl{$K^{pub}_A$}\\
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2. & \bl{$B \to A :$} & \bl{$K^{pub}_B$}\\
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3. & & \bl{$\{A,m\}_{K^{pub}_B} \;\mapsto\; H_1,H_2$}\\
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& & \bl{$\{B,m'\}_{K^{pub}_A} \;\mapsto\; M_1,M_2$}\\
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4. & \bl{$A \to B :$} & \bl{$H_1$}\\
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5. & \bl{$B \to A :$} & \bl{$\{H_1, M_1\}_{K^{pub}_A}$}\\
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6. & \bl{$A \to B :$} & \bl{$\{H_2, M_1\}_{K^{pub}_B}$}\\
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7. & \bl{$B \to A :$} & \bl{$M_2$}
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\end{tabular}
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\end{center}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c]
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\frametitle{Splitting Messages}
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\begin{center}
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$\underbrace{\texttt{\Grid{0X1peUVTGJK+H70mMjAM8p}}}_{\bl{\{A,m\}_{K^{pub}_B}}}$
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\end{center}
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\begin{center}
|
|
324 |
$\underbrace{\texttt{\Grid{0X1peUVTGJK}}}_{\bl{H_1}}$\quad
|
|
325 |
$\underbrace{\texttt{\Grid{+H70mMjAM8p}}}_{\bl{H_2}}$
|
|
326 |
\end{center}
|
|
327 |
||
328 |
\begin{itemize}
|
|
329 |
\item you can also use the even and odd bytes |
|
330 |
\item the point is you cannot decrypt the halves, even if you |
|
331 |
have the key |
|
332 |
\end{itemize}
|
|
333 |
||
334 |
||
335 |
\end{frame}
|
|
336 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
337 |
||
338 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
339 |
\begin{frame}[c]
|
|
340 |
||
341 |
\begin{center}
|
|
342 |
\begin{tabular}{l@{\hspace{9mm}}l}
|
|
343 |
\begin{tabular}[t]{@{}l@{}}
|
|
344 |
\bl{$A \to C : K^{pub}_A$}\\
|
|
345 |
\bl{$C \to B : K^{pub}_C$}\\
|
|
346 |
\bl{$B \to C : K^{pub}_B$}\\
|
|
347 |
\bl{$C \to A : K^{pub}_C$}\medskip\\
|
|
348 |
\bl{$\{A,m\}_{K^{pub}_C} \;\mapsto\; H_1,H_2$}\\
|
|
349 |
\bl{$\{B,m'\}_{K^{pub}_C} \;\mapsto\; M_1,M_2$}\bigskip\\
|
|
350 |
\bl{$\{C,a\}_{K^{pub}_B} \;\mapsto\; C_1,C_2$}\\
|
|
351 |
\bl{$\{C,b\}_{K^{pub}_A} \;\mapsto\; D_1,D_2$}
|
|
352 |
\end{tabular} &
|
|
353 |
\begin{tabular}[t]{@{}l@{}}
|
|
354 |
\bl{$A \to C : H_1$}\\
|
|
355 |
\bl{$C \to B : C_1$}\\
|
|
356 |
\bl{$B \to C : \{C_1, M_1\}_{K^{pub}_C}$}\\
|
|
357 |
\bl{$C \to A : \{H_1, D_1\}_{K^{pub}_A}$}\\
|
|
358 |
\bl{$A \to C : \{H_2, D_1\}_{K^{pub}_C}$}\\
|
|
359 |
\bl{$C \to B : \{C_2, M_1\}_{K^{pub}_B}$}\\
|
|
360 |
\bl{$B \to C : M_2$}\\
|
|
361 |
\bl{$C \to A : D_2$}
|
|
362 |
\end{tabular}
|
|
363 |
\end{tabular}
|
|
364 |
\end{center}\pause
|
|
365 |
||
366 |
\footnotesize |
|
367 |
\bl{$m$} = How is your grandmother? \bl{$m'$} = How is the
|
|
368 |
weather today in London? |
|
369 |
||
370 |
\end{frame}
|
|
371 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
372 |
|
| 495 | 373 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
374 |
\begin{frame}[c]
|
|
375 |
||
376 |
\begin{itemize}
|
|
377 |
\item you have to ask something that cannot be imitated |
|
378 |
(requires \bl{$A$} and \bl{$B$} know each other)
|
|
379 |
\item what happens if \bl{$m$} and \bl{$m'$} are voice
|
|
380 |
messages?\bigskip\pause |
|
381 |
||
382 |
\item So \bl{$C$} can either leave the communication unchanged,
|
|
383 |
or invent a complete new conversation |
|
384 |
||
385 |
\end{itemize}
|
|
386 |
||
387 |
\end{frame}
|
|
388 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
389 |
||
390 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
391 |
\begin{frame}[c]
|
|
392 |
||
393 |
\begin{itemize}
|
|
394 |
\item the moral: establishing a secure connection from |
|
395 |
``zero'' is almost impossible---you need to rely on some |
|
396 |
established trust\medskip |
|
397 |
||
398 |
\item that is why PKI relies on certificates, which however are |
|
399 |
badly, badly realised |
|
400 |
||
401 |
\end{itemize}
|
|
402 |
||
403 |
\end{frame}
|
|
404 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
405 |
||
406 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
407 |
\begin{frame}[c]
|
|
408 |
\frametitle{Trusted Third Parties}
|
|
409 |
||
410 |
Simple protocol for establishing a secure connection via a |
|
411 |
mutually trusted 3rd party (server): |
|
412 |
||
413 |
\begin{center}
|
|
414 |
\begin{tabular}{r@ {\hspace{1mm}}l}
|
|
415 |
\bl{$A \rightarrow S :$} & \bl{$A, B$}\\
|
|
416 |
\bl{$S \rightarrow A :$} & \bl{$\{K_{AB}, \{K_{AB}\}_{K_{BS}} \}_{K_{AS}}$}\\
|
|
417 |
\bl{$A \rightarrow B :$} & \bl{$\{K_{AB}\}_{K_{BS}} $}\\
|
|
418 |
\bl{$A \rightarrow B :$} & \bl{$\{m\}_{K_{AB}}$}\\
|
|
419 |
\end{tabular}
|
|
420 |
\end{center}
|
|
421 |
||
422 |
\end{frame}
|
|
423 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
424 |
||
425 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
426 |
\begin{frame}[c]
|
|
427 |
\frametitle{PKI: The Main Idea}
|
|
428 |
||
429 |
\begin{itemize}
|
|
430 |
\item the idea is to have a certificate authority (CA) |
|
431 |
\item you go to the CA to identify yourself |
|
432 |
\item CA: ``I, the CA, have verified that public key |
|
433 |
\bl{$P^{pub}_{Bob}$} belongs to Bob''\bigskip
|
|
434 |
\item CA must be trusted by everybody\medskip |
|
435 |
\item certificates are time limited, and can be revoked |
|
436 |
||
437 |
\item What happens if CA issues a false certificate? Who pays in case of loss? (VeriSign |
|
438 |
explicitly limits liability to \$100.) |
|
439 |
\end{itemize}
|
|
440 |
||
441 |
\end{frame}
|
|
442 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
443 |
||
444 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
445 |
\begin{frame}[c]
|
|
446 |
\frametitle{PKI: Chains of Trust}
|
|
447 |
||
448 |
\begin{center}
|
|
449 |
\begin{tikzpicture}[scale=1,
|
|
450 |
node/.style={
|
|
451 |
rectangle,rounded corners=3mm, |
|
452 |
very thick,draw=black!50,minimum height=18mm, minimum width=23mm, |
|
453 |
top color=white,bottom color=black!20}] |
|
454 |
||
455 |
\node (A) at (0,0) [node] {};
|
|
456 |
\node [below right] at (A.north west) |
|
457 |
{\small\begin{tabular}{@{}l}CA\\Root Cert.\end{tabular}};
|
|
458 |
||
459 |
\node (B) at (4,0) [node] {};
|
|
460 |
\node [below right=1mm] at (B.north west) |
|
461 |
{\mbox{}\hspace{-1mm}\small
|
|
462 |
\begin{tabular}{@{}l}Subordinate\\ CA\end{tabular}};
|
|
463 |
||
464 |
\node (C) at (8,0) [node] {};
|
|
465 |
\node [below right] at (C.north west) |
|
466 |
{\small\begin{tabular}{@{}l}Server\\ Bank.com\end{tabular}};
|
|
467 |
||
468 |
\draw [->,line width=4mm] (A) -- (B); |
|
469 |
\draw [->,line width=4mm] (B) -- (C); |
|
470 |
||
471 |
\node (D) at (6,-3) [node] {};
|
|
472 |
\node [below right] at (D.north west) |
|
473 |
{\small\begin{tabular}{@{}l}Browser\\ Root Store\end{tabular}};
|
|
474 |
||
475 |
\node (E) at (2,-3) [node] {};
|
|
476 |
\node [below right] at (E.north west) |
|
477 |
{\small\begin{tabular}{@{}l}Browser\\ Vendor\end{tabular}};
|
|
478 |
||
479 |
\draw [->,line width=4mm] (E) -- (D); |
|
480 |
\end{tikzpicture}
|
|
481 |
\end{center}
|
|
482 |
||
483 |
\begin{itemize}
|
|
484 |
\item CAs make almost no money anymore, because of stiff |
|
485 |
competition |
|
486 |
\item browser companies are not really interested in security; |
|
487 |
only in market share |
|
488 |
\end{itemize}
|
|
489 |
||
490 |
\end{frame}
|
|
491 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
492 |
||
493 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
494 |
\begin{frame}[c]
|
|
495 |
\frametitle{PKI: Weaknesses}
|
|
496 |
||
497 |
CAs just cannot win (make any profit):\medskip |
|
498 |
||
499 |
\begin{itemize}
|
|
500 |
\item there are hundreds of CAs, which issue millions of |
|
501 |
certificates and the error rate is small |
|
502 |
||
503 |
\item users (servers) do not want to pay or pay as little as |
|
504 |
possible\bigskip |
|
505 |
||
506 |
\item a CA can issue a certificate for any domain not needing |
|
507 |
any permission (CAs are meant to undergo audits, |
|
508 |
but\ldots DigiNotar) |
|
509 |
||
510 |
\item if a CA has issued many certificates, it ``becomes too |
|
511 |
big to fail'' |
|
512 |
||
513 |
\item Can we be sure CAs are not just frontends of some |
|
514 |
government organisation? |
|
515 |
||
516 |
\end{itemize}
|
|
517 |
||
518 |
\end{frame}
|
|
519 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
520 |
||
521 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
522 |
\begin{frame}[c]
|
|
523 |
\frametitle{PKI: Weaknesses}
|
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
524 |
|
|
277
d6dc6f0e3556
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
525 |
\begin{itemize}
|
|
280
b732a63c17b8
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
279
diff
changeset
|
526 |
|
| 495 | 527 |
\item many certificates are issued via Whois, whether you own |
528 |
the domain\ldots if you hijacked a domain, it is easy to |
|
529 |
obtain certificates\medskip |
|
530 |
||
531 |
\item the revocation mechanism does not work (Chrome has given |
|
532 |
up on general revocation lists)\medskip |
|
533 |
||
534 |
\item lax approach to validation of certificates |
|
535 |
(Have you ever bypassed certification warnings?)\medskip |
|
536 |
||
537 |
\item sometimes you want to actually install invalid |
|
538 |
certificates (self-signed) |
|
539 |
||
540 |
\end{itemize}
|
|
541 |
||
542 |
\end{frame}
|
|
543 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
544 |
||
545 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
546 |
\begin{frame}[c]
|
|
547 |
\frametitle{PKI: Attacks}
|
|
548 |
||
549 |
\begin{itemize}
|
|
550 |
||
551 |
\item Go directly after root certificates |
|
552 |
\begin{itemize}
|
|
553 |
\item governments can demand private keys\smallskip |
|
554 |
\item 10 years ago it was estimated that breaking a 1024 bit |
|
555 |
key takes one year and costs 10 - 30 Mio \$; this is now |
|
556 |
reduced to 1 Mio \$ |
|
557 |
\end{itemize}
|
|
558 |
||
559 |
\item Go after buggy implementations of certificate |
|
560 |
validation\smallskip |
|
561 |
||
562 |
\item Social Engineering |
|
563 |
\begin{itemize}
|
|
564 |
\item in 2001 somebody pretended to be |
|
565 |
from Microsoft and asked for two code-signing |
|
566 |
certificates |
|
567 |
\end{itemize}\bigskip
|
|
568 |
\end{itemize}
|
|
569 |
||
570 |
\small The eco-system is completely broken (it relies on |
|
571 |
thousands of entities to do the right thing). Maybe DNSSEC |
|
572 |
where keys can be attached to domain names is a way out. |
|
573 |
||
574 |
\end{frame}
|
|
575 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
576 |
||
577 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
578 |
\begin{frame}[c]
|
|
579 |
\frametitle{Real Attacks}
|
|
580 |
||
581 |
\begin{itemize}
|
|
582 |
||
583 |
\item In 2011, DigiNotar (Dutch company) was the first CA that |
|
584 |
got compromised comprehensively, and where many |
|
585 |
fraudulent certificates were issued to the wild. It |
|
586 |
included approximately 300,000 IP addresses, mostly |
|
587 |
located in Iran. The attackers (in Iran?) were likely |
|
588 |
interested ``only'' in collecting gmail passwords.\medskip |
|
589 |
||
590 |
\item The Flame malware piggy-bagged on this attack by |
|
591 |
advertising malicious Windows updates to some targeted |
|
592 |
systems (mostly in Iran, Israel, Sudan). |
|
|
280
b732a63c17b8
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
279
diff
changeset
|
593 |
|
|
277
d6dc6f0e3556
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
594 |
\end{itemize}
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
595 |
|
|
279
5616e664c020
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
278
diff
changeset
|
596 |
\end{frame}
|
|
277
d6dc6f0e3556
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
597 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
598 |
|
|
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
599 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
280
b732a63c17b8
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
279
diff
changeset
|
600 |
\begin{frame}[c]
|
| 495 | 601 |
\frametitle{PKI is Broken}
|
|
280
b732a63c17b8
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
279
diff
changeset
|
602 |
|
| 495 | 603 |
\begin{itemize}
|
|
281
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
604 |
|
| 495 | 605 |
\item PKI and certificates are meant to protect you against |
606 |
MITM attacks, but if the attack occurs your are |
|
607 |
presented with a warning and you need to decide whether |
|
608 |
you are under attack.\medskip |
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
609 |
|
| 495 | 610 |
\item Webcontent gets often loaded from 3rd-party servers, |
611 |
which might not be secured\medskip |
|
612 |
||
613 |
\item Misaligned incentives: browser vendors are not |
|
614 |
interested in breaking webpages with invalid |
|
615 |
certificates |
|
|
129
10526c967679
added slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
128
diff
changeset
|
616 |
|
| 495 | 617 |
\end{itemize}
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
618 |
|
|
280
b732a63c17b8
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
279
diff
changeset
|
619 |
\end{frame}
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
620 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
621 |
|
|
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
622 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
623 |
\begin{frame}[c]
|
| 495 | 624 |
|
625 |
Why are there so many invalid certificates?\bigskip |
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
626 |
|
|
277
d6dc6f0e3556
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
627 |
\begin{itemize}
|
| 495 | 628 |
|
629 |
\item insufficient name coverage (www.example.com should |
|
630 |
include example.com) |
|
631 |
||
632 |
\item IoT: many appliances have web-based admin interfaces; |
|
633 |
the manufacturer cannot know under which IP and domain name |
|
634 |
the appliances are run (so cannot install a valid certificate) |
|
635 |
||
636 |
\item expired certificates, or incomplete chains of trust |
|
637 |
(servers are supposed to supply them) |
|
638 |
||
639 |
\end{itemize}
|
|
640 |
||
641 |
\end{frame}
|
|
642 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
|
281
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
643 |
|
| 495 | 644 |
% |
645 |
% |
|
646 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
647 |
%\begin{frame}[c]
|
|
648 |
%\frametitle{Best Practices}
|
|
649 |
% |
|
650 |
%{\bf Principle 1:} Every message should say what it means: the
|
|
651 |
%interpretation of a message should not depend on the |
|
652 |
%context.\bigskip\pause |
|
653 |
% |
|
654 |
%{\bf Principle 2:} If the identity of a principal is essential
|
|
655 |
%to the meaning of a message, it is prudent to mention the |
|
656 |
%principal’s name explicitly in the message (though |
|
657 |
%difficult).\bigskip |
|
658 |
% |
|
659 |
%\end{frame}
|
|
660 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
661 |
% |
|
662 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
663 |
%\begin{frame}[c]
|
|
664 |
%\frametitle{Best Practices}
|
|
665 |
% |
|
666 |
%{\bf Principle 3:} Be clear about why encryption is being
|
|
667 |
%done. Encryption is not wholly cheap, and not asking precisely |
|
668 |
%why it is being done can lead to redundancy. Encryption is not |
|
669 |
%synonymous with security. % |
|
670 |
% |
|
671 |
%\small |
|
672 |
%\begin{center}
|
|
673 |
%Possible Uses of Encryption % |
|
674 |
% |
|
675 |
%\begin{itemize}
|
|
676 |
%\item Preservation of confidentiality: \bl{$\{X\}_K$} only those that have \bl{$K$} may recover \bl{$X$}.
%\item Guarantee authenticity: The partner is indeed some particular principal.
%\item Guarantee confidentiality and authenticity: binds two parts of a message ---
|
|
677 |
%\bl{$\{X,Y\}_K$} is not the same as \bl{$\{X\}_K$} and \bl{$\{Y\}_K$}.
|
|
678 |
%\end{itemize}
|
|
679 |
%\end{center}
|
|
680 |
% |
|
681 |
%\end{frame}
|
|
682 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
683 |
% |
|
684 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
685 |
%\begin{frame}[c]
|
|
686 |
%\frametitle{Best Practices}
|
|
687 |
% |
|
688 |
%{\bf Principle 4:} The protocol designers should know which
|
|
689 |
%trust relations their protocol depends on, and why the |
|
690 |
%dependence is necessary. The reasons for particular trust |
|
691 |
%relations being acceptable should be explicit though they will |
|
692 |
%be founded on judgment and policy rather than on |
|
693 |
%logic.\bigskip |
|
694 |
% |
|
695 |
% %Example Certification Authorities: CAs are trusted to certify |
|
696 |
%a key only after proper steps have been taken to identify the |
|
697 |
%principal that owns it. |
|
698 |
% |
|
699 |
%\end{frame}
|
|
700 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
701 |
% |
|
702 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
703 |
%\begin{frame}[c]
|
|
704 |
%\frametitle{Formal Methods}
|
|
705 |
% |
|
706 |
%Ross Anderson about the use of Logic:\bigskip |
|
707 |
% |
|
708 |
%\begin{quote}
|
|
709 |
%Formal methods can be an excellent way of finding |
|
710 |
%bugs in security protocol designs as they force the designer |
|
711 |
%to make everything explicit and thus confront difficult design |
|
712 |
%choices that might otherwise be fudged. |
|
713 |
%\end{quote}
|
|
714 |
% |
|
715 |
%\end{frame}
|
|
716 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
717 |
% |
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
718 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
719 |
\begin{frame}[c]
|
| 495 | 720 |
\frametitle{Mid-Term}
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
721 |
|
|
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
722 |
\begin{itemize}
|
| 495 | 723 |
\item homework, handouts, programs\ldots |
724 |
\end{itemize}\bigskip\bigskip\bigskip
|
|
725 |
||
726 |
\begin{center}
|
|
727 |
{\huge\bf\alert{Any Questions?}}
|
|
728 |
\end{center}
|
|
729 |
||
730 |
\end{frame}
|
|
731 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
|
281
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
732 |
|
| 495 | 733 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
734 |
\begin{frame}[c]
|
|
735 |
\frametitle{Security Engineering}
|
|
736 |
||
737 |
\begin{center}
|
|
738 |
\begin{tabular}{cc}
|
|
739 |
\raisebox{-0.8mm}{\includegraphics[scale=0.28]{../pics/flight.jpg}} &
|
|
740 |
\includegraphics[scale=0.31]{../pics/airbus.jpg}\\
|
|
741 |
\small Wright brothers, 1901 & \small Airbus, 2005 \\ |
|
742 |
\end{tabular}
|
|
743 |
\end{center}
|
|
|
281
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
744 |
|
| 495 | 745 |
\end{frame}
|
746 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
|
126
b091e0abb894
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
90
diff
changeset
|
747 |
|
| 60 | 748 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
749 |
\begin{frame}[c]
|
|
| 495 | 750 |
\frametitle{1st Lecture}
|
| 60 | 751 |
|
| 495 | 752 |
\begin{itemize}
|
753 |
\item chip-and-pin, banks vs.~customers |
|
754 |
\begin{quote}\small\rm
|
|
755 |
the one who can improve security should also be |
|
756 |
liable for the losses |
|
757 |
\end{quote}\pause\bigskip
|
|
758 |
||
759 |
\item hashes and salts to guarantee data integrity\medskip |
|
760 |
\item storing passwords (you should know the difference between |
|
761 |
brute force attacks and dictionary attacks; how do salts help?) |
|
762 |
\end{itemize}
|
|
763 |
||
764 |
\end{frame}
|
|
765 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
|
282
4a0071e26cb5
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
281
diff
changeset
|
766 |
|
| 495 | 767 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
768 |
\begin{frame}[c]
|
|
769 |
\frametitle{1st Lecture: Cookies}
|
|
770 |
||
771 |
\begin{itemize}
|
|
772 |
\item good uses of cookies?\medskip |
|
| 60 | 773 |
|
| 495 | 774 |
\item bad uses of cookies: snooping, tracking, profiling\ldots |
775 |
the ``disadvantage'' is that the user is in |
|
776 |
\alert{control}, because you can delete them
|
|
777 |
||
778 |
\begin{center} ``Please track me using cookies.''
|
|
779 |
\end{center}\bigskip\pause
|
|
780 |
||
781 |
\item fingerprinting beyond browser cookies |
|
782 |
\begin{quote}\small\rm
|
|
783 |
Pixel Perfect: Fingerprinting Canvas in HTML5\\ |
|
784 |
(a research paper from 2012)\\ |
|
785 |
\footnotesize |
|
786 |
\url{http://cseweb.ucsd.edu/~hovav/papers/ms12.html}
|
|
787 |
\end{quote}
|
|
788 |
\end{itemize}
|
|
|
281
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
789 |
|
|
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
790 |
\end{frame}
|
| 495 | 791 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
792 |
||
793 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
794 |
\begin{frame}[c]
|
|
795 |
\frametitle{1st Lecture: Cookies}
|
|
796 |
||
797 |
\begin{itemize}
|
|
798 |
\item a bit of JavaScript and HTML5 + canvas\medskip |
|
799 |
\begin{center}
|
|
800 |
\begin{tabular}{cc}
|
|
801 |
Firefox & Safari\\ |
|
802 |
\includegraphics[scale=0.31]{../pics/firefox1.png} &
|
|
803 |
\includegraphics[scale=0.31]{../pics/safari1.png} \\
|
|
804 |
\tiny |
|
805 |
\pcode{55b2257ad0f20ecbf927fb66a15c61981f7ed8fc} &
|
|
806 |
\tiny |
|
807 |
\pcode{17bc79f8111e345f572a4f87d6cd780b445625d3}
|
|
808 |
\end{tabular}
|
|
809 |
\end{center}\bigskip
|
|
810 |
||
811 |
\item\small no actual drawing needed\pause |
|
812 |
\item\small in May 2014 a crawl of 100,000 popular |
|
813 |
webpages revealed 5.5\% already use canvas |
|
814 |
fingerprinting\smallskip |
|
815 |
\begin{center}\scriptsize
|
|
816 |
\url{https://securehomes.esat.kuleuven.be/~gacar/persistent/the_web_never_forgets.pdf}
|
|
817 |
\end{center}
|
|
818 |
\end{itemize}
|
|
819 |
||
820 |
\end{frame}
|
|
821 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
822 |
||
823 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
824 |
\begin{frame}[c]
|
|
825 |
\frametitle{1st Lecture: Cookies}
|
|
826 |
||
827 |
Remember the small web-app I showed you where a cookie |
|
828 |
protected a counter?\bigskip |
|
829 |
||
830 |
\begin{itemize}
|
|
831 |
\item NYT, the cookie looks the ``resource'' - harm\medskip |
|
832 |
\item imaginary discount unlocked by cookie - no harm |
|
833 |
\end{itemize}
|
|
834 |
||
835 |
\end{frame}
|
|
836 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
|
130
4e8482e50590
more slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
129
diff
changeset
|
837 |
|
|
282
4a0071e26cb5
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
281
diff
changeset
|
838 |
|
|
4a0071e26cb5
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
281
diff
changeset
|
839 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 495 | 840 |
\begin{frame}[t]
|
841 |
\frametitle{2nd Lecture: E-Voting}
|
|
842 |
||
843 |
Where are paper ballots better than voice voting?\bigskip |
|
844 |
||
845 |
\begin{itemize}
|
|
846 |
\item Integrity |
|
847 |
\item \alert{Ballot Secrecy}
|
|
848 |
\item Voter Authentication |
|
849 |
\item Enfranchisement |
|
850 |
\item Availability |
|
851 |
\end{itemize}
|
|
852 |
||
853 |
\end{frame}
|
|
854 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
855 |
||
856 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
857 |
\begin{frame}[t]
|
|
858 |
\frametitle{2nd Lecture: E-Voting}
|
|
859 |
||
860 |
\begin{itemize}
|
|
861 |
\item recently an Australian parliamentary committee |
|
862 |
found: e-voting is highly vulnerable to hacking and Australia |
|
863 |
will not use it any time soon\bigskip\pause |
|
864 |
\item Alex Halderman, Washington D.C.~hack |
|
|
282
4a0071e26cb5
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
281
diff
changeset
|
865 |
\begin{center}
|
| 495 | 866 |
\scriptsize |
867 |
\url{https://jhalderm.com/pub/papers/dcvoting-fc12.pdf}
|
|
868 |
\end{center}\medskip
|
|
869 |
||
870 |
\item PDF-ballot tampering at the wireless router (the modification |
|
871 |
is nearly undetectable and leaves no traces; MITM attack with firmware |
|
872 |
updating) |
|
873 |
\begin{center}
|
|
874 |
\scriptsize |
|
875 |
\url{http://galois.com/wp-content/uploads/2014/11/technical-hack-a-pdf.pdf}
|
|
|
282
4a0071e26cb5
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
281
diff
changeset
|
876 |
\end{center}
|
|
4a0071e26cb5
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
281
diff
changeset
|
877 |
|
| 495 | 878 |
\end{itemize}
|
|
282
4a0071e26cb5
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
281
diff
changeset
|
879 |
|
|
4a0071e26cb5
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
281
diff
changeset
|
880 |
\end{frame}
|
| 495 | 881 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
282
4a0071e26cb5
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
281
diff
changeset
|
882 |
|
|
4a0071e26cb5
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
281
diff
changeset
|
883 |
|
|
277
d6dc6f0e3556
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
884 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 495 | 885 |
\tikzset{alt/.code args={<#1>#2#3#4}{%
|
886 |
\alt<#1>{\pgfkeysalso{#2}}{\pgfkeysalso{#3}} % \pgfkeysalso doesn't change the path
|
|
887 |
}} |
|
888 |
||
889 |
\begin{frame}[t]
|
|
890 |
\frametitle{\begin{tabular}{c}3rd Lecture:\\ Buffer Overflow Attacks\end{tabular}}
|
|
891 |
||
892 |
\begin{itemize}
|
|
893 |
\item the problem arises from the way C/C++ organises its function calls\\[-8mm]\mbox{}
|
|
894 |
\end{itemize}
|
|
|
130
4e8482e50590
more slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
129
diff
changeset
|
895 |
|
| 495 | 896 |
\begin{center}
|
897 |
\begin{tikzpicture}[scale=1]
|
|
898 |
%\draw[black!10,step=2mm] (0,0) grid (9,4); |
|
899 |
%\draw[black!10,thick,step=10mm] (0,0) grid (9,4); |
|
900 |
||
901 |
\node at (0.5,4.5) {\small\begin{tabular}{l}main\\[-2mm] prog.\end{tabular}};
|
|
902 |
\draw[line width=0mm, white, alt=<2->{fill=red}{fill=blue}] (0,2.5) rectangle (1,3.8);
|
|
903 |
\draw[line width=0mm, white, alt=<9->{fill=red}{fill=blue}] (0,0.2) rectangle (1,0.5);
|
|
904 |
\draw[line width=1mm, alt=<3->{fill=yellow}{fill=blue}] (0,2.0) rectangle (1,2.5);
|
|
905 |
\draw[line width=1mm, alt=<6->{fill=red}{fill=blue}] (0,1.0) rectangle (1,2.0);
|
|
906 |
\draw[line width=1mm, alt=<7->{fill=yellow}{fill=blue}] (0,0.5) rectangle (1,1.0);
|
|
907 |
\draw[line width=1mm] (0,0) -- (0,4); |
|
908 |
\draw[line width=1mm] (1,0) -- (1,4); |
|
909 |
||
910 |
\node at (3.5,3.5) {\small\begin{tabular}{l}fact(n)\end{tabular}};
|
|
911 |
\draw[line width=1mm, alt=<{4-5,8}>{fill=red}{fill=blue}] (3,1.0) rectangle (4,3.0);
|
|
|
130
4e8482e50590
more slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
129
diff
changeset
|
912 |
|
| 495 | 913 |
\onslide<3-4>{\draw[->, line width=1mm,red] (1,2.3) to node [above,sloped,midway] {n=4} (3,3);}
|
914 |
\onslide<5>{\draw[<-, line width=1mm,red] (1,2.3) to node [above,sloped,midway] {res=24} (3,1);}
|
|
915 |
||
916 |
\onslide<7-8>{\draw[->, line width=1mm,red] (1,0.8) to node [above,sloped,midway] {n=3} (3,3);}
|
|
917 |
\onslide<9>{\draw[<-, line width=1mm,red] (1,0.8) to node [above,sloped,midway] {res=6} (3,1);}
|
|
918 |
||
919 |
||
920 |
\node at (7.75,3.9) {\small\begin{tabular}{l}stack\end{tabular}};
|
|
921 |
\draw[line width=1mm] (7,3.5) -- (7,0.5) -- (8.5,0.5) -- (8.5,3.5); |
|
|
277
d6dc6f0e3556
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
922 |
|
| 495 | 923 |
\onslide<3,4,7,8>{
|
924 |
\node at (7.75, 1.4) {ret};
|
|
925 |
\draw[line width=1mm] (7,1.1) -- (8.5,1.1); |
|
926 |
\node at (7.75, 2.0) {sp};
|
|
927 |
\draw[line width=1mm] (7,2.3) -- (8.5,2.3); |
|
928 |
} |
|
929 |
\onslide<3,4>{
|
|
930 |
\node at (7.75, 0.8) {4};
|
|
931 |
\draw[line width=1mm] (7,1.7) -- (8.5,1.7); |
|
932 |
} |
|
933 |
\onslide<7,8>{
|
|
934 |
\node at (7.75, 0.8) {3};
|
|
935 |
\draw[line width=1mm] (7,1.7) -- (8.5,1.7); |
|
936 |
} |
|
937 |
||
938 |
||
939 |
\end{tikzpicture}
|
|
940 |
\end{center}
|
|
|
130
4e8482e50590
more slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
129
diff
changeset
|
941 |
|
|
281
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
942 |
\end{frame}
|
|
130
4e8482e50590
more slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
129
diff
changeset
|
943 |
|
|
277
d6dc6f0e3556
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
944 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
281
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
945 |
\begin{frame}[t]
|
|
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
946 |
|
|
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
947 |
\begin{center}
|
| 495 | 948 |
\begin{tikzpicture}[scale=1]
|
949 |
%\draw[black!10,step=2mm] (0,0) grid (9,4); |
|
950 |
%\draw[black!10,thick,step=10mm] (0,0) grid (9,4); |
|
951 |
||
952 |
\node at (0.5,4.5) {\small\begin{tabular}{l}main\\[-2mm] prog.\end{tabular}};
|
|
953 |
\draw[line width=0mm, white, alt=<2->{fill=red}{fill=blue}] (0,2.5) rectangle (1,3.8);
|
|
954 |
\draw[line width=1mm, white, fill=blue] (0,1.0) rectangle (1,2.0); |
|
955 |
\draw[line width=1mm, alt=<3->{fill=yellow}{fill=blue}] (0,2.0) rectangle (1,2.5);
|
|
956 |
\draw[line width=1mm] (0,0) -- (0,4); |
|
957 |
\draw[line width=1mm] (1,0) -- (1,4); |
|
958 |
||
959 |
\node at (3.5,3.5) {\small\begin{tabular}{l}fact(n)\end{tabular}};
|
|
960 |
\draw[line width=0mm, alt=<{4-}>{red, fill=red}{blue, fill=blue}] (3,2.8) rectangle (4,3.0);
|
|
961 |
\draw[line width=0mm, alt=<{5-}>{red, fill=red}{blue, fill=blue}] (3,2.8) rectangle (4,2.0);
|
|
962 |
\draw[line width=0mm, alt=<{7-}>{red, fill=red}{blue, fill=blue}] (3,2.0) rectangle (4,1.0);
|
|
963 |
\draw[line width=1mm] (3,1.0) rectangle (4,3.0); |
|
964 |
||
965 |
\onslide<3->{\draw[->, line width=1mm,red] (1,2.3) to node [above,sloped,midway] {n=4} (3,3);}
|
|
966 |
\onslide<5->{\draw[<-, line width=2mm,red] (4,2) to node [above,sloped,midway]
|
|
967 |
{\begin{tabular}{l}user\\[-1mm] input\end{tabular}} (6,2);}
|
|
968 |
\onslide<8->{\draw[<-, line width=1mm,red] (1,-2) to (3,1);}
|
|
969 |
||
970 |
\node at (7.75,3.9) {\small\begin{tabular}{l}stack\end{tabular}};
|
|
971 |
\draw[line width=1mm] (7,3.5) -- (7,-0.1) -- (8.5,-0.1) -- (8.5,3.5); |
|
972 |
||
973 |
\onslide<3->{
|
|
974 |
\node at (7.75, 0.2) {4};
|
|
975 |
\draw[line width=1mm,alt=<6->{fill=red}{fill=white}] (7,0.5) rectangle (8.5,1.1);
|
|
976 |
\node at (7.75, 0.8) {\alt<6->{@a\#}{ret}};
|
|
977 |
\draw[line width=1mm,alt=<6->{fill=red}{fill=white}] (7,1.1) rectangle (8.5,1.7);
|
|
978 |
\node at (7.75, 1.4) {\alt<6->{!?w;}sp};
|
|
979 |
} |
|
980 |
||
981 |
\onslide<4->{
|
|
982 |
\draw[line width=1mm,fill=red] (7,1.7) rectangle (8.5,3.0); |
|
983 |
\node[white] at (7.75, 2.4) {buffer};
|
|
984 |
} |
|
985 |
||
|
281
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
986 |
\end{tikzpicture}
|
|
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
987 |
\end{center}
|
|
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
988 |
|
|
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
989 |
\end{frame}
|
|
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
990 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
991 |
|
|
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
992 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 495 | 993 |
\begin{frame}[t]
|
994 |
\frametitle{\begin{tabular}{c}3rd Lecture:\\[-3mm]
|
|
995 |
Buffer Overflow Attacks\end{tabular}}
|
|
|
130
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parents:
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|
996 |
|
| 495 | 997 |
US National Vulnerability Database\\ |
998 |
\small(636 out of 6675 in 2014) |
|
| 60 | 999 |
|
| 495 | 1000 |
\begin{center}
|
1001 |
\begin{tikzpicture}
|
|
1002 |
\begin{axis}[
|
|
1003 |
xlabel={year},
|
|
1004 |
ylabel={\% of total attacks},
|
|
1005 |
ylabel style={yshift=0em},
|
|
1006 |
enlargelimits=false, |
|
1007 |
xtick={1997,1999,...,2015},
|
|
1008 |
xmin=1996.5, |
|
1009 |
xmax=2016, |
|
1010 |
ymax=21, |
|
1011 |
ytick={0,5,...,20},
|
|
1012 |
scaled ticks=false, |
|
1013 |
axis lines=left, |
|
1014 |
width=11cm, |
|
1015 |
height=5cm, |
|
1016 |
ybar, |
|
1017 |
nodes near coords= |
|
1018 |
{\footnotesize
|
|
1019 |
$\pgfmathprintnumber[fixed,fixed zerofill,precision=1,use comma]{\pgfkeysvalueof{/data point/y}}$},
|
|
1020 |
x tick label style={font=\scriptsize,/pgf/number format/1000 sep={}}]
|
|
1021 |
\addplot |
|
1022 |
table [x=Year,y=Percentage] {../handouts/bufferoverflows.data};
|
|
1023 |
\end{axis}
|
|
1024 |
\end{tikzpicture}
|
|
1025 |
\end{center}
|
|
|
277
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
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|
1026 |
|
| 495 | 1027 |
\scriptsize |
1028 |
\url{http://web.nvd.nist.gov/view/vuln/statistics}
|
|
|
281
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
1029 |
\end{frame}
|
| 495 | 1030 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
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parents:
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|
1031 |
|
|
281
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
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|
1032 |
|
|
130
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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|
1033 |
|
|
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parents:
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|
1034 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 495 | 1035 |
\begin{frame}[t]
|
1036 |
\frametitle{\begin{tabular}{c}4th Lecture:\\ Unix Access Control\end{tabular}}
|
|
|
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parents:
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|
1037 |
|
|
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
1038 |
\begin{itemize}
|
| 495 | 1039 |
\item privileges are specified by file access permissions (``everything is a file'') |
1040 |
\end{itemize}\medskip
|
|
|
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parents:
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|
1041 |
|
| 495 | 1042 |
\begin{center}
|
1043 |
\begin{tikzpicture}[scale=1]
|
|
1044 |
||
1045 |
\draw[line width=1mm] (-.3, 0) rectangle (1.5,2); |
|
1046 |
\draw (4.7,1) node {Internet};
|
|
1047 |
\draw (-2.7,1.7) node {\footnotesize Application};
|
|
1048 |
\draw (0.6,1.7) node {\footnotesize Interface};
|
|
1049 |
\draw (0.6,-0.4) node {\footnotesize \begin{tabular}{c}unprivileged\\[-1mm] process\end{tabular}};
|
|
1050 |
\draw (-2.7,-0.4) node {\footnotesize \begin{tabular}{c}privileged\\[-1mm] process\end{tabular}};
|
|
1051 |
||
1052 |
\draw[line width=1mm] (-1.8, 0) rectangle (-3.6,2); |
|
1053 |
||
1054 |
\draw[white] (1.7,1) node (X) {};
|
|
1055 |
\draw[white] (3.7,1) node (Y) {};
|
|
1056 |
\draw[red, <->, line width = 2mm] (X) -- (Y); |
|
1057 |
||
1058 |
\draw[red, <->, line width = 1mm] (-0.6,1) -- (-1.6,1); |
|
1059 |
\end{tikzpicture}
|
|
1060 |
\end{center}
|
|
1061 |
||
1062 |
\begin{itemize}
|
|
1063 |
\item the idea is to make the attack surface smaller and |
|
1064 |
mitigate the consequences of an attack |
|
|
277
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parents:
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diff
changeset
|
1065 |
\end{itemize}
|
|
d6dc6f0e3556
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
1066 |
|
|
294
5e8ffb58bdaa
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
283
diff
changeset
|
1067 |
\end{frame}
|
| 495 | 1068 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 61 | 1069 |
|
|
277
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
1070 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 495 | 1071 |
\begin{frame}[fragile,t]
|
1072 |
\frametitle{\begin{tabular}{c}4th Lecture:\\ Unix Access Control\end{tabular}}
|
|
| 61 | 1073 |
|
| 495 | 1074 |
\begin{itemize}
|
1075 |
\item when a file with setuid is executed, the resulting process will assume the |
|
1076 |
UID given to the owner of the file |
|
1077 |
\end{itemize}
|
|
| 61 | 1078 |
|
| 495 | 1079 |
\footnotesize\tt |
|
277
d6dc6f0e3556
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
1080 |
\begin{center}
|
| 495 | 1081 |
\begin{verbatim}
|
1082 |
$ ls -ld . * */* |
|
1083 |
drwxr-xr-x 1 ping staff 32768 Apr 2 2010 . |
|
1084 |
-rw----r-- 1 ping students 31359 Jul 24 2011 manual.txt |
|
1085 |
-r--rw--w- 1 bob students 4359 Jul 24 2011 report.txt |
|
1086 |
-rwsr--r-x 1 bob students 141359 Jun 1 2013 microedit |
|
1087 |
dr--r-xr-x 1 bob staff 32768 Jul 23 2011 src |
|
1088 |
-rw-r--r-- 1 bob staff 81359 Feb 28 2012 src/code.c |
|
1089 |
-r--rw---- 1 emma students 959 Jan 23 2012 src/code.h |
|
1090 |
\end{verbatim}
|
|
|
277
d6dc6f0e3556
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
135
diff
changeset
|
1091 |
\end{center}
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
1092 |
|
|
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
1093 |
|
| 495 | 1094 |
\end{frame}
|
1095 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
1096 |
|
|
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
1097 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 495 | 1098 |
\begin{frame}[t]
|
1099 |
\frametitle{\begin{tabular}{c}4th Lecture:\\ Unix Access Control\end{tabular}}
|
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
1100 |
|
| 495 | 1101 |
\begin{itemize}
|
1102 |
\item Alice wants to have her files readable, |
|
1103 |
\alert{except} for her office mates.\bigskip
|
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
1104 |
|
| 495 | 1105 |
\item make sure you understand the setuid and setgid bits; |
1106 |
why are they necessary for login and passwd |
|
1107 |
\end{itemize}
|
|
|
128
4e108563716c
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
126
diff
changeset
|
1108 |
|
|
281
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
1109 |
|
|
98403100cea7
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
280
diff
changeset
|
1110 |
\end{frame}
|
| 495 | 1111 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
423
11b46fa92a85
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
422
diff
changeset
|
1112 |
|
|
11b46fa92a85
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
422
diff
changeset
|
1113 |
|
| 59 | 1114 |
\end{document}
|
1115 |
||
1116 |
%%% Local Variables: |
|
1117 |
%%% mode: latex |
|
1118 |
%%% TeX-master: t |
|
1119 |
%%% End: |
|
1120 |