sen-material: comparison slides/slides04.tex

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-:ced8b6208e36
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 \end{frame}
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 \begin{frame}[c]
+\frametitle{Survey: Thanks!}
+\small
+\begin{itemize}
+\item ``Would be good, if you provide more detailed explanations. I feel
+your slides are not as structured as they could be.''
+\item Please consider reference book chapters to cover core subject
+areas.''\pause
+\item ``The homework questions don't come directly from the
+slides. So must go look things up.''
+\item ``Could you please put the homework answers online, perhaps
+just before the exam. That's late enough where we should have done
+it and if not, we're screwed already then.''
+\item ``Could you provide a brief basic answers to sheets for reference
+and not to be relied on.''
+\end{itemize}
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[c]
 \begin{center}
 \includegraphics[scale=0.45]{../pics/trainwreck.jpg}\\
 last week: buffer overflow attacks
 \end{center}
 \small
 As a proof-of-concept, the following URL allows
 attackers to control the return value saved on
 the stack (the vulnerability is triggered when
-executing "/usr/sbin/widget"):
+executing \pcode{"/usr/sbin/widget"}):
 \begin{center}\footnotesize
 \pcode{curl http://<target ip>/post_login.xml?hash=AAA...AAABBBB}
 \end{center}
 \begin{tabular}{@{}ll}
 Discovery date: & 06/03/2013\\
 Release date:   & 02/08/2013
-\end{tabular}
+\end{tabular}\bigskip
+\footnotesize
 \hfill\url{http://roberto.greyhats.it/advisories/20130801-dlink-dir645.txt}
 \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 "What is this string," I hear you ask?
 You will laugh: it is
-\begin{center}
+\begin{center}\large
 \pcode{xmlset_roodkcableoj28840ybtide}
 \end{center}
 \end{quote}\bigskip\bigskip
 \hfill\footnotesize October 15, 2013\\
 configurations (\pcode{/tmp} not mounted noexec). Steps to reproduce:
 \begin{itemize}
 \item Put an executable file named \pcode{update} with non-root owner in /tmp (not
 mounted noexec, obviously)
-\item Run chkrootkit (as uid 0)
+\item Run chkrootkit (as uid \pcode{0})
 \end{itemize}
 Result: The file \pcode{/tmp/update} will be executed as root, thus effectively
 rooting your box, if malicious content is placed inside the file.
 \begin{frame}[c]
 \frametitle{Access Control in Unix}
 \begin{itemize}
 \item access control provided by the OS
-\item authenticate principals (login)
+\item authenticate principals
-\item mediate access to files, ports, processes according to \alert{roles} (user ids)\\
+\item mediate access to files, ports, processes etc according to
-\item roles get attached with privileges\bigskip\\%
+\alert{roles} (user ids)\\
+\item roles get attached with privileges\bigskip\\
 \hspace{8mm}
 \begin{bubble}[8cm]
 \alert{principle of least privilege:}\\
-users and programs should only have as much privilege as they need
+users and programs should only have as much privilege as they need to
+accomplish a task
 \end{bubble}
 \end{itemize}
 \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \texttt{id cu}
 \end{center}\medskip\pause
 \item non-root users are not allowed to change the UID --- would break
 access control
-\item but needed for example for \texttt{passwd}
+\item but needed for example for accessing \texttt{passwd}
 \end{itemize}
 \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[c]
 \frametitle{Setuid and Setgid}
 The solution is that Unix file permissions are 9 + \underline{2 Bits}:
-\alert{Setuid} and \alert{Setgid} Bits
+\alert{Setuid} and \alert{Setgid} bits
 \begin{itemize}
 \item When a file with setuid is executed, the resulting process will
-assume the UID given to the owner of the file.
+assume the UID given to the \underline{owner} of the file.
 \item This enables users to create processes as root (or another
 user).\bigskip
 \item Essential for changing passwords, for example.
 \end{itemize}
 \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[c]
-\frametitle{Access Control}
-\begin{itemize}
-\item \bl{Discretionary Access Control:}\mbox{}\medskip\\
-\small Access to objects (files, directories, devices, etc.) is permitted
-based on user identity. Each object is owned by a user. Owners can
-specify freely (at their discretion) how they want to share their objects
-with other users, by specifying which other users can have which
-form of access to their objects.\medskip
-Discretionary access control is implemented on any multi-user OS
-(Unix, Windows NT, etc.).
-\end{itemize}
-\end{frame}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\begin{frame}[c]
-\frametitle{Access Control}
-\begin{itemize}
-\item \bl{Mandatory Access Control:}\mbox{}\medskip\\
-\small Access to objects is controlled by a system-wide policy, for example
-to prevent certain flows of information. In some forms, the system maintains
-security labels for both objects and subjects (processes, users), based on
-which access is granted or denied. Labels can change as the result of an
-access. Security policies are enforced without the cooperation of users or
-application programs.\medskip
-This is implemented today in special military operating system versions
-(SELinux).
-\end{itemize}
-\end{frame}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\begin{frame}[c]
 \frametitle{\Large Discretionary Access Control}
-In its most generic form usually given by an Access Control Matrix
+\begin{itemize}
-of the form
+\item Access to objects (files, directories, devices, etc.) is
+permitted based on user identity. Each object is owned by a
+user. Owners can specify freely (at their discretion) how they want to
+share their objects with other users, by specifying which other users
+can have which form of access to their objects.\medskip
+\item Discretionary access control is implemented on any modern multi-user
+OS (Unix, Windows NT, etc.).
+\end{itemize}
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[c]
+\frametitle{\Large Mandatory Access Control}
+\begin{itemize}
+\item Access to objects is controlled by a system-wide policy, for
+example to prevent certain flows of information. In some forms, the
+system maintains security labels for both objects and subjects
+(processes, users) based on which access is granted or
+denied. Labels can change as the result of an access. Security
+policies are enforced without the cooperation of users or
+programs.\medskip
+\item This is implemented in banking or military operating system
+versions (SELinux).
+\end{itemize}
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[c]
+\frametitle{\Large Discretionary Access Control}
+In its most generic form usually given by an \alert{Access Control
+Matrix} of the form
 \begin{center}
 \begin{tabular}{r|c|c|c}
-& /mail/jane & edit.exe & sendmail \\\hline
+& /mail/jane & edit.exe & postfix \\\hline
 jane          & r, w & r, x & r, x\\\hline
 john          & $\varnothing$ & r, w, x&  r, x\\\hline
-sendmail  & a & $\varnothing$ &  r, x\\
+postfix  & a & $\varnothing$ &  r, x\\
 \end{tabular}
 \end{center}
 access privileges: {\bf r}ead, {\bf w}rite, e{\bf x}ecute, {\bf a}ppend
 \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[c]
 \small
-\lstinputlisting[numbers=none,xleftmargin=-6mm]{lst}
+\lstinputlisting[language={},numbers=none,xleftmargin=-6mm]{lst}
 \begin{center}
-\begin{tabular}{ll}
+\begin{tabular}{@{\hspace{-24mm}}ll}
-Members of group staff: & ping, bob, emma\\
+members of group staff: & ping, bob, emma\\
-Members of group students: & emma\\
+members of group students: & emma\\
 \end{tabular}
 \end{center}
 \begin{center}
 \begin{tabular}{@{\hspace{-7mm}}r|c|c|c|c|c@{}}
 \item Restrictions to allowed information flows are not decided at the
 user's discretion (as with Unix \pcode{chmod}), but instead enforced
 by system policies.
 \item Mandatory access control mechanisms are aimed in particular at
-preventing policy violations by untrusted application software,
+preventing policy violations by untrusted programs, which typically
-which typically have at least the same access privileges as the
+have at least the same access privileges as the invoking
-invoking user.\medskip
+user.\medskip\pause
-Simple example: Air Gap Security. Uses completely separate network
+Simple example: Air Gap Security. Uses a completely separate network
 and computer hardware for different application classes.
 \end{itemize}
 \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[c]
-\frametitle{The Bell/LaPadula Model}
+\frametitle{The Bell-LaPadula Model}
+\small
 \begin{itemize}
 \item Formal policy model for mandatory access control in a military
 multi-level security environment. All subjects (processes, users,
 terminals, files, windows, connections) are labeled
 \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[c]
+\frametitle{\Large Cryptographic Protocol Failures}
+Ross Anderson and Roger Needham wrote:\bigskip
+\begin{quote}\rm
+A lot of the recorded frauds were the result of this kind of blunder,
+or from management negligence pure and simple. \alert{However, there
+have been a significant number of cases where the designers
+protected the right things, used cryptographic algorithms which were
+not broken, and yet found that their systems were still successfully
+attacked.}
+\end{quote}
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \mode<presentation>{
 \begin{frame}[c]
 \frametitle{Authentication Protocols}

changeset 243	dd94cbf9eba7
parent 241	07e4d8f64ca8
child 244	9fc6ec22ad82