# Cis Ubuntu1804 V220 1 8 8 > Ensure GDM autorun-never is enabled - Skill: `cyberstrikeus/cis-ubuntu1804-v220-1-8-8` (Agent Skill) - Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu1804-v220-1-8-8` - Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu1804-v220-1-8-8/raw - Safety review: PASS (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/cyberstrikeus/cis-ubuntu1804-v220-1-8-8 --- # 1.8.8 Ensure GDM autorun-never is enabled (Automated) ## Profile Applicability - Level 1 - Server - Level 1 - Workstation ## Description The `autorun-never` setting allows the GNOME Desktop Display Manager to disable autorun through GDM. ## Rationale Malware on removable media may taking advantage of Autorun features when the media is inserted into a system and execute. ## Audit Procedure ### Command Line Run the following script to verify that `autorun-never` is set to `true` for GDM: ```bash #!/usr/bin/env bash { l_pkgoutput="" l_output="" l_output2="" # 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 -s" 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")" fi # If the profile name exist, continue checks if [ -n "$l_gpname" ]; then l_gpdir="/etc/dconf/db/$l_gpname.d" # Check if profile file exists if grep -Pq -- "^\h*system-db:$l_gpname\b" /etc/dconf/profile/*; then l_output="$l_output\n - dconf database profile file \"$(grep -Pl -- "^\h*system-db:$l_gpname\b" /etc/dconf/profile/*)\" exists" else l_output2="$l_output2\n - dconf database profile isn't set" fi # Check if the dconf database file exists if [ -f "/etc/dconf/db/$l_gpname" ]; then l_output="$l_output\n - The dconf database \"$l_gpname\" exists" else l_output2="$l_output2\n - The dconf database \"$l_gpname\" doesn't exist" fi # check if the dconf database directory exists if [ -d "$l_gpdir" ]; then l_output="$l_output\n - The dconf directory \"$l_gpdir\" exitst" else l_output2="$l_output2\n - The dconf directory \"$l_gpdir\" doesn't exist" fi # check autorun-never setting if grep -Pqrs -- '^\h*autorun-never\h*=\h*true\b' "$l_kfile"; then l_output="$l_output\n - \"autorun-never\" is set to true in: \"$l_kfile\"" else l_output2="$l_output2\n - \"autorun-never\" is not set correctly" fi else # Settings don't exist. Nothing further to check l_output2="$l_output2\n - \"autorun-never\" is not set" fi else l_output="$l_output\n - GNOME Desktop Manager package is not installed on the system\n - Recommendation is not applicable" fi # Report results. If no failures output in l_output2, we pass if [ -z "$l_output2" ]; then echo -e "\n- Audit Result:\n ** PASS **\n$l_output\n" else echo -e "\n- Audit Result:\n ** FAIL **\n - Reason(s) for audit failure:\n$l_output2\n" [ -n "$l_output" ] && echo -e "\n- Correctly set:\n$l_output\n" fi } ``` ## Remediation ### Command Line Run the following script to set `autorun-never` to `true` for GDM users: ```bash #!/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 -s" 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' "$l_kfile"; then sed -ri 's/^\s*autorun-never\s*=\s*\S+/autorun-never=true' "$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 } ``` ## Default Value false ## References 1. NIST SP 800-53 Rev. 5: CM-1, CM-2, CM-6, CM-7, IA-5 ## CIS Controls | Controls Version | Control | IG 1 | IG 2 | IG 3 | | ---------------- | ----------------------------------------------------- | ---- | ---- | ---- | | v8 | 10.3 Disable Autorun and Autoplay for Removable Media | X | X | X | | v7 | 8.5 Configure Devices Not To Auto-run Content | X | X | X | ## MITRE ATT&CK Mappings | Techniques / Sub-techniques | Tactics | Mitigations | | --------------------------- | -------------- | ----------- | | T1091, T1091.000 | TA0001, TA0008 | M1028 |