sandevistan-server-hardening / CIS_Ubuntu_22.04_LTS_Benchmark_v1.0.0

Audit script based on CIS Ubuntu 22.04 LTS Benchmark v1.0.0
MIT License
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1.8.9 Ensure GDM autorun-never is not overridden #55

Open scfast opened 1 year ago

scfast commented 1 year ago

Profile Applicability:  Level 1 - Server  Level 1 - Workstation

Description: 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

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

Audit: Run the following script to verify 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\n
# 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="$l_pkgoutput\n -
Package: \"$l_pn\" exists on the system\n - checking configuration"
done
# Check configuration (If applicable)
if [ -n "$l_pkgoutput" ]; then
l_output="" l_output2=""
# Look for idle-delay to determine profile in use, needed for remaining
tests
l_kfd="/etc/dconf/db/$(grep -Psril '^\h*autorun-never\b'
/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 -Piq '^\h*\/org/gnome\/desktop\/media-handling\/autorun-
never\b' "$l_kfd"; then

l_output="$l_output\n - \"autorun-never\" is locked in \"$(grep -
Pil '^\h*\/org/gnome\/desktop\/media-handling\/autorun-never\b' "$l_kfd")\""
else
l_output2="$l_output2\n - \"autorun-never\" is not locked"
fi
else
l_output2="$l_output2\n - \"autorun-never\" is not set so it can not
be locked"
fi
else
l_output="$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
[ -n "$l_pkgoutput" ] && echo -e "\n$l_pkgoutput"
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
}