Detections
Analytics
1.8.9 Ensure GDM autorun-never is not overridden
Information
The autorun-never setting allows the GNOME Desktop Display Manager to disable autorun through GDM.By using the lockdown mode in dconf, you can prevent users from changing specific settings.
To lock down a dconf key or subpath, create a locks subdirectory in the keyfile directory. The files inside this directory contain a list of keys or subpaths to lock. Just as with the keyfiles, you may add any number of files to this directory.
Example Lock File:
# Lock desktop media-handling settings
/org/gnome/desktop/media-handling/autorun-never
Malware on removable media may taking advantage of Autorun features when the media is inserted into a system and execute.
Solution
Run the following script to ensure that autorun-never=true cannot be overridden:#!/usr/bin/env bash
{
# Check if GNOME Desktop Manager is installed. If package isn't installed, recommendation is Not Applicable
# determine system's package manager
l_pkgoutput=""
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="y" && echo -e "
- Package: \"$l_pn\" exists on the system
- remediating configuration if needed"
done
# Check configuration (If applicable)
if [ -n "$l_pkgoutput" ]; then
# Look for autorun to determine profile in use, needed for remaining tests
l_kfd="/etc/dconf/db/$(grep -Psril '^h*autorun-neverb' /etc/dconf/db/*/ | awk -F'/' '{split($(NF-1),a,".");print a[1]}').d" #set directory of key file to be locked
if [ -d "$l_kfd" ]; then # If key file directory doesn't exist, options can't be locked
if grep -Prisq '^h*/org/gnome/desktop/media-handling/autorun-neverb' "$l_kfd"; then
echo " - \"autorun-never\" is locked in \"$(grep -Pril '^h*/org/gnome/desktop/media-handling/autorun-neverb' "$l_kfd")\""
else
echo " - creating entry to lock \"autorun-never\""
[ ! -d "$l_kfd"/locks ] && echo "creating directory $l_kfd/locks" && mkdir "$l_kfd"/locks
{
echo -e '
# Lock desktop media-handling autorun-never setting'
echo '/org/gnome/desktop/media-handling/autorun-never'
} >> "$l_kfd"/locks/00-media-autorun
fi
else
echo -e " - \"autorun-never\" is not set so it can not be locked
- Please follow Recommendation \"Ensure GDM autorun-never is enabled\" and follow this Recommendation again"
fi
# update dconf database
dconf update
else
echo -e " - GNOME Desktop Manager package is not installed on the system
- Recommendation is not applicable"
fi
}
See Also
Item Details
Audit Name: CIS Ubuntu Linux 20.04 LTS Workstation L1 v2.0.1
Category: MEDIA PROTECTION
References: 800-53|MP-7, CSCv7|8.5
Plugin: Unix
Control ID: 28d2984638cdca35158d316e129a9dede15a99c966a44b9af5bfc779e638bf5d