3.1.4 Ensure SCTP is disabled

Audit

Run the following script to verify sctp is disabled:

#!/usr/bin/env bash
{
 l_output="" l_output2=""
 l_mname="sctp" # set module name
 # Check if the module exists on the system
 if [ -z "$(modprobe -n -v "$l_mname" 2>&1 | grep -Pi -- "\h*modprobe:\h+FATAL:\h+Module\h+$l_mname\h+not\h+found\h+in\h+directory")" ]; then
 # Check how module will be loaded
 l_loadable="$(modprobe -n -v "$l_mname")"
 [ "$(wc -l <<< "$l_loadable")" -gt "1" ] && l_loadable="$(grep -P -- "(^\h*install|\b$l_mname)\b" <<< "$l_loadable")"
 if grep -Pq -- '^\h*install \/bin\/(true|false)' <<< "$l_loadable"; then
 l_output="$l_output\n - module: \"$l_mname\" is not loadable: \"$l_loadable\""
 else
 l_output2="$l_output2\n - module: \"$l_mname\" is loadable: \"$l_loadable\""
 fi
 # Check is the module currently loaded
 if ! lsmod | grep "$l_mname" > /dev/null 2>&1; then
 l_output="$l_output\n - module: \"$l_mname\" is not loaded"
 else
 l_output2="$l_output2\n - module: \"$l_mname\" is loaded"
 fi
 # Check if the module is deny listed
 if modprobe --showconfig | grep -Pq -- "^\h*blacklist\h+$l_mname\b"; then
 l_output="$l_output\n - module: \"$l_mname\" is deny listed in: \"$(grep -Pl -- "^\h*blacklist\h+$l_mname\b" /etc/modprobe.d/*)\""
 else
 l_output2="$l_output2\n - module: \"$l_mname\" is not deny listed"
 fi
 else
 l_output="$l_output\n - Module \"$l_mname\" doesn't exist on the system"
 fi
 # Report results. If no failures output in l_output2, we pass
 if [ -z "$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

Run the following script to disable sctp:

#!/usr/bin/env bash
{
 l_mname="sctp" # set module name
 # Check if the module exists on the system
 if [ -z "$(modprobe -n -v "$l_mname" 2>&1 | grep -Pi -- "\h*modprobe:\h+FATAL:\h+Module\h+$l_mname\h+not\h+found\h+in\h+directory")" ]; then
 # Remediate loadable
 l_loadable="$(modprobe -n -v "$l_mname")"
 [ "$(wc -l <<< "$l_loadable")" -gt "1" ] && l_loadable="$(grep -P -- "(^\h*install|\b$l_mname)\b" <<< "$l_loadable")"
 if ! grep -Pq -- '^\h*install \/bin\/(true|false)' <<< "$l_loadable"; then
 echo -e " - setting module: \"$l_mname\" to be not loadable"
 echo -e "install $l_mname /bin/false" >> /etc/modprobe.d/"$l_mname".conf
 fi
 # Remediate loaded
 if lsmod | grep "$l_mname" > /dev/null 2>&1; then
 echo -e " - unloading module \"$l_mname\""
 modprobe -r "$l_mname"
 fi
 # Remediate deny list
 if ! modprobe --showconfig | grep -Pq -- "^\h*blacklist\h+$l_mname\b"; then
 echo -e " - deny listing \"$l_mname\""
 echo -e "blacklist $l_mname" >> /etc/modprobe.d/"$l_mname".conf
 fi
 else
 echo -e " - Nothing to remediate\n - Module \"$l_mname\" doesn't exist on the system"
 fi
}