diff -r 770b58a7d754 -r 9019f84ef99c hws/hw04.tex
--- a/hws/hw04.tex	Mon Sep 28 21:02:01 2015 +0100
+++ b/hws/hw04.tex	Mon Sep 28 23:17:35 2015 +0100
@@ -8,6 +8,10 @@
 \begin{enumerate}
 \item What does the principle of least privilege say?
 
+\item How can you exploit the fact that every night root has a cron
+  job that deletes the files in \texttt{/tmp}? (Hint: cron-attack)
+
+
 \item In which of the following situations can the access control mechanism of Unix
 file permissions be used?