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_loopback_is_configured.sh

@@ -0,0 +1,94 @@
+#!/bin/bash
+
+# run-shellcheck
+#
+# CIS Debian Hardening
+#
+
+#
+# Ensure nftables loopback traffic is configured (Automated)
+#
+
+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 loopback traffic is configured"
+
+# This function will be called if the script status is on enabled / audit mode
+audit() {
+    NFTABLES_LOOPBACK=1
+    NFTABLES_LOOPBACK_DROP=1
+    NFTABLES_IPV6_LOOPBACK_DROP=1
+
+    if nft list ruleset 2>/dev/null | awk '/hook input/,/}/' | grep 'iif "lo" accept'; then
+        NFTABLES_LOOPBACK=0
+        ok "loopback is configured for nftables"
+    else
+        crit "loopback is not configured for nftables"
+    fi
+
+    if nft list ruleset 2>/dev/null | awk '/hook input/,/}/' | grep "ip saddr 127.0.0.1.*drop"; then
+        NFTABLES_LOOPBACK_DROP=0
+        ok "nftables input loopack traffic is dropped"
+    else
+        crit "nftables input loopack traffic is not dropped"
+    fi
+
+    is_ipv6_enabled
+    if [ "$FNRET" -eq 0 ]; then
+        if nft list ruleset 2>/dev/null | awk '/hook input/,/}/' | grep "ip6 saddr ::1.*drop"; then
+            NFTABLES_IPV6_LOOPBACK_DROP=0
+            ok "nftables input loopack traffic is dropped"
+        else
+            crit "nftables input loopack traffic is not dropped"
+        fi
+    fi
+}
+
+# This function will be called if the script status is on enabled mode
+apply() {
+    if [ "$NFTABLES_LOOPBACK" -ne 0 ]; then
+        info "adding nftables loopback configuration"
+        nft add rule inet filter input iif lo accept
+    fi
+
+    if [ "$NFTABLES_LOOPBACK_DROP" -ne 0 ]; then
+        info "adding nftables loopback drop configuration"
+        nft create rule inet filter input ip saddr 127.0.0.0/8 counter drop
+    fi
+
+    is_ipv6_enabled
+    if [ "$FNRET" -eq 0 ] && [ "$NFTABLES_IPV6_LOOPBACK_DROP" -ne 0 ]; then
+        info "adding nftables ipv6 loopback drop configuration"
+        nft add rule inet filter input ip6 saddr ::1 counter drop
+    fi
+}
+
+# This function will check config parameters required
+check_config() {
+    :
+}
+
+# Source Root Dir Parameter
+if [ -r /etc/default/cis-hardening ]; then
+    # shellcheck source=../../debian/default
+    . /etc/default/cis-hardening
+fi
+
+if [ -z "$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