feat: add debian12 scripts

- nftables_loopback_is_configured.sh 	-> 4.2.6
- nftables_established_connections.sh 	-> 4.2.7
- iptables_flushed_with_nftables.sh 	-> 4.2.3
- ufw_loopback_is_configured.sh 	-> 4.1.4
- ufw_outbound_connection.sh 		-> 4.1.5
- ufw_default_deny.sh 			-> 4.1.7
- ufw_rules_them_all.sh 		-> 4.1.6

bin/hardening/nftables_established_connections.sh

@@ -0,0 +1,92 @@
+#!/bin/bash
+
+# run-shellcheck
+#
+# CIS Debian Hardening
+#
+
+#
+# Ensure nftables outbound and established connections are configured (Manual)
+#
+
+set -e # One error, it's over
+set -u # One variable unset, it's over
+
+# shellcheck disable=2034
+HARDENING_LEVEL=2
+# shellcheck disable=2034
+DESCRIPTION="Ensure nftables outbound and established connections are configured"
+
+NFTABLES_INPUT_ALLOWED=""
+NFTABLES_OUTPUT_ALLOWED=""
+
+# This function will be called if the script status is on enabled / audit mode
+audit() {
+    local status
+
+    for allowed in $NFTABLES_INPUT_ALLOWED; do
+        protocol=$(awk -F ':' '{print $1}' <<<"$allowed")
+        state=$(awk -F ':' '{print $2}' <<<"$allowed")
+
+        if $SUDO_CMD nft list ruleset 2>/dev/null | awk '/hook input/,/}/' | grep -E "ip protocol $protocol ct state $state accept"; then
+            ok "'$protocol' is accepted for state(s) '$state' in nftables 'input'"
+        else
+            crit "'$protocol' is not accepted for state(s) '$state' in nftables 'input'"
+        fi
+    done
+
+    for allowed in $NFTABLES_OUTPUT_ALLOWED; do
+        protocol=$(awk -F ':' '{print $1}' <<<"$allowed")
+        state=$(awk -F ':' '{print $2}' <<<"$allowed")
+
+        if $SUDO_CMD nft list ruleset 2>/dev/null | awk '/hook output/,/}/' | grep -E "ip protocol $protocol ct state $state accept"; then
+            ok "'$protocol' is accepted for state(s) '$state' in nftables 'output'"
+        else
+            crit "'$protocol' is not accepted for state(s) '$state' in nftables 'output'"
+        fi
+    done
+
+}
+
+# This function will be called if the script status is on enabled mode
+apply() {
+    info "Please review the rules according to your site policy, and update the check configuration if needed"
+
+}
+
+create_config() {
+    cat <<EOF
+# shellcheck disable=2034
+status=audit
+# Put here the input allowed protocols, space separated
+# protocol:states
+NFTABLES_INPUT_ALLOWED="tcp:established udp:established icmp:established"
+NFTABLES_OUTPUT_ALLOWED="tcp:established,related,new udp:established,related,new icmp:established,related,new"
+EOF
+}
+
+# This function will check config parameters required
+check_config() {
+    :
+}
+
+# Source Root Dir Parameter
+if [ -r /etc/default/cis-hardening ]; then
+    # shellcheck source=../../debian/default
+    . /etc/default/cis-hardening
+fi
+
+if [ -z "$CIS_LIB_DIR" ]; then
+    echo "There is no /etc/default/cis-hardening file nor cis-hardening directory in current environment."
+    echo "Cannot source CIS_LIB_DIR variable, aborting."
+    exit 128
+fi
+
+# Main function, will call the proper functions given the configuration (audit, enabled, disabled)
+if [ -r "${CIS_LIB_DIR}"/main.sh ]; then
+    # shellcheck source=../../lib/main.sh
+    . "${CIS_LIB_DIR}"/main.sh
+else
+    echo "Cannot find main.sh, have you correctly defined your root directory? Current value is $CIS_LIB_DIR in /etc/default/cis-hardening"
+    exit 128
+fi