1.8.8 Ensure GDM autorun-never is enabled

Information

The autorun-never setting allows the GNOME Desktop Display Manager to disable autorun through GDM.

Malware on removable media may take advantage of Autorun features when the media is inserted into a system and execute.

Solution

Run the following script to set autorun-never to true for GDM users:

#!/usr/bin/env bash

{
l_pkgoutput="" l_output="" l_output2=""
l_gpname="local" # Set to desired dconf profile name (default is local)
# Check if GNOME Desktop Manager is installed. If package isn't installed, recommendation is Not Applicable\n
# determine system's package manager
if command -v dpkg-query > /dev/null 2>&1; then
l_pq="dpkg-query -W"
elif command -v rpm > /dev/null 2>&1; then
l_pq="rpm -q"
fi
# Check if GDM is installed
l_pcl="gdm gdm3" # Space separated list of packages to check
for l_pn in $l_pcl; do
$l_pq "$l_pn" > /dev/null 2>&1 && l_pkgoutput="$l_pkgoutput\n - Package: \"$l_pn\" exists on the system\n - checking configuration"
done
echo -e "$l_pkgoutput"
# Check configuration (If applicable)
if [ -n "$l_pkgoutput" ]; then
echo -e "$l_pkgoutput"
# Look for existing settings and set variables if they exist
l_kfile="$(grep -Prils -- '^\h*autorun-never\b' /etc/dconf/db/*.d)"
# Set profile name based on dconf db directory ({PROFILE_NAME}.d)
if [ -f "$l_kfile" ]; then
l_gpname="$(awk -F\/ '{split($(NF-1),a,".");print a[1]}' <<< "$l_kfile")"
echo " - updating dconf profile name to \"$l_gpname\""
fi
[ ! -f "$l_kfile" ] && l_kfile="/etc/dconf/db/$l_gpname.d/00-media-autorun"
# Check if profile file exists
if grep -Pq -- "^\h*system-db:$l_gpname\b" /etc/dconf/profile/*; then
echo -e "\n - dconf database profile exists in: \"$(grep -Pl -- "^\h*system-db:$l_gpname\b" /etc/dconf/profile/*)\""
else
[ ! -f "/etc/dconf/profile/user" ] && l_gpfile="/etc/dconf/profile/user" || l_gpfile="/etc/dconf/profile/user2"
echo -e " - creating dconf database profile"
{
echo -e "\nuser-db:user"
echo "system-db:$l_gpname"
} >> "$l_gpfile"
fi
# create dconf directory if it doesn't exists
l_gpdir="/etc/dconf/db/$l_gpname.d"
if [ -d "$l_gpdir" ]; then
echo " - The dconf database directory \"$l_gpdir\" exists"
else
echo " - creating dconf database directory \"$l_gpdir\""
mkdir "$l_gpdir"
fi
# check autorun-never setting
if grep -Pqs -- '^\h*autorun-never\h*=\h*true\b' "$l_kfile"; then
echo " - \"autorun-never\" is set to true in: \"$l_kfile\""
else
echo " - creating or updating \"autorun-never\" entry in \"$l_kfile\""
if grep -Psq -- '^\h*autorun-never' "$l_kfile"; then
sed -ri 's/(^\s*autorun-never\s*=\s*)(\S+)(\s*.*)$/\1true \3/' "$l_kfile"
else
! grep -Psq -- '\^\h*\[org\/gnome\/desktop\/media-handling\]\b' "$l_kfile" && echo '[org/gnome/desktop/media-handling]' >> "$l_kfile"
sed -ri '/^\s*\[org\/gnome\/desktop\/media-handling\]/a \\nautorun-never=true' "$l_kfile"
fi
fi
else
echo -e "\n - GNOME Desktop Manager package is not installed on the system\n - Recommendation is not applicable"
fi
# update dconf database
dconf update
}

See Also

https://workbench.cisecurity.org/benchmarks/15289

Item Details

Category: MEDIA PROTECTION

References: 800-53|MP-7, CSCv7|8.5

Plugin: Unix

Control ID: 24da9220be76681bbefc6ec77c50b402a67298efd8acb329cbee75229e5fa01e