So in order for this vulnerability to be exploited, the attacker needs
to have a local account on the machine correct? Your exploitation explanation
is a bit construed. Any more info / demostrations would be helpful.
-Erik
On 18 Sep 2006 21:26:52 -0000
fribitch@organic.com wrote:
Background:
ARD allows unix commands to be remotely sent from an admin workstation. These
commands can be run as root, because the ard administrator can be given sudo
access. This exploit involves sending a unix command as root to install a
package that was copied to /tmp/. In this case, the app is Adobe CS 2.0 using
the adobe silent installation script. The script will mount disk images as
root, run the install, then cleanup. If a standard user is logged in, they
will see an icon on the dock for the install, but should never see anything
besides the icon.
The issue:
The process LoginWindow is owned by the logged in user. If the system is at
the login window, then the process LoginWindow is owned by root. If the
system is mounting a disk image visible only to root, then the image will try
to appear on the desktop. Clicking the mouse will force the desktop to
appear, as well as the menus. A user sitting that the system will then see a
finder window, and the root users home directory. The login window can be
ignored, and the user has full root access. Files can be deleted without
authentication, and the trash can be emptied. If a user tries to login, the
login window will check their credentials, but they will end up logging in to
the root desktop with root privileges.
The workaround:
If you are trying to run a remote install script such as the Adobe Silent
installer, use the lock screen feature in ARD. This locks the users desktop
until the admin is done doing their thing.
The end result:
http://www.flickr.com/photos/metfoo/246858852/
Adobes script:
#!/bin/sh
#
# Example script to run the Adobe Creative Suite 2 Installer silently.
#
#
# Copyright: 2005 Adobe Systems, Inc.
#
#
function detach_images
{
# umount any previous mounted installer images
for NUMBER in 1 2 3 4
do
MOUNTED_POINT="/Volumes/Adobe Creative Suite Disk ${NUMBER} "
/sbin/mount |/usr/bin/grep "${MOUNTED_POINT}" 2>/dev/null
if [ $? -eq 0 ] ; then
echo "Another \"${MOUNT_POINT}\" already attached."
DEVICE=`/sbin/mount |/usr/bin/grep "${MOUNTED_POINT}"
2>/dev/null |/usr/bin/cut -d" " -f1`
if [ -b "${DEVICE}" ] ; then
/usr/bin/hdiutil detach "${DEVICE}"
echo "Detaching \"${DEVICE}\"..."
fi
fi
done
}
SAVEDIR="`pwd`"
trap 'cd "${SAVEDIR}"' EXIT
if [ $# -ne 2 ] ; then
echo "usage: $0 <image folder> <config filepath>"
exit 1
fi
IMGDIR=$1
CONFIG=$2
# Check OS Version, Minimum is 10.2.8
OSVERSION=`/usr/bin/sw_vers |/usr/bin/grep ProductVersion |/usr/bin/cut -d:
-f2`
MAJORVER=`echo ${OSVERSION} | /usr/bin/cut -d . -f2`
MVTEMP=`echo ${OSVERSION} | /usr/bin/cut -d. -f3`
MINORVER=${MVTEMP:-0}
if [ ${MAJORVER} -lt 3 ] ; then
# if less then 10.3
if [ ${MAJORVER} -ne 2 ] ; then
echo "This version of MacOS (${OSVERSION}) is not
supported."
exit 1;
else
if [ ${MINORVER} -lt 8 ] ; then
echo "This version of MacOS (${OSVERSION}) is not
supported."
exit 1;
fi
fi
HDIUTIL_OPTIONS=
else
# additional hdiutil options for 10.3 or above system
HDIUTIL_OPTIONS="-private -noverify"
fi
# Check root volume is HFS
/sbin/mount -t hfs |/usr/bin/grep " / " 2>/dev/null
if [ $? -ne 0 ] ; then
echo "Root volume is not a HFS volume."
exit 5
fi
# validate the arguments
if [ ! -d "$IMGDIR" ] ; then
echo "$IMGDIR" does not exist.
exit 2
fi
if [ ! -r "$CONFIG" ] ; then
echo "$CONFIG" does not exist.
exit 3
fi
# Check running as root
MYUID=`/usr/bin/id -u`
if [ ${MYUID} -ne 0 ] ; then
echo "You need to be root to run the Adobe Creative Suite 2 Installer."
exit 4
fi
cd "${IMGDIR}"
IMGCOUNT=`/bin/ls -l *.dmg 2>/dev/null | /usr/bin/wc -l`
if [ -z "${IMGCOUNT}" -o "${IMGCOUNT}" = "0" ] ; then
echo "No disk image found in "${IMGDIR}"."
exit 2
fi
#detach any already attached installer images
detach_images
# Mount the disk images for the installer CDs
for DMG in *.dmg
do
# mount the remaining disk images
echo
echo "--- Attaching Installer disk image ${NUMBER}..."
echo /usr/bin/hdiutil attach -verbose -readonly ${HDIUTIL_OPTIONS}
"${DMG}"
/usr/bin/hdiutil attach -verbose -readonly ${HDIUTIL_OPTIONS} "${DMG}"
if [ $? -ne 0 ] ; then
echo "Error in attaching installer disk image: \"${DMG}\""
exit 6
fi
done
echo
echo
echo "---- Starting the Adobe Creative Suite Installer..."
echo
"/Volumes/Adobe Creative Suite Disk 1/Adobe
Installer.app/Contents/MacOS/Adobe Installer" --batch -c "${CONFIG}"
INSTALLATION_RESULT=$?
echo
#now detach attached installer images
detach_images
exit ${INSTALLATION_RESULT}
--
Erik Lat
System Engineer
Lextech Global Services
