feat: add debian12 scripts

- iptables_loopback.sh -> 4.3.2.2 - iptables_rule_them_all.sh -> 4.3.2.4 - iptables_outbound_established.sh -> 4.3.2.3 - ip6tables_loopback.sh -> 4.3.3.2 - ip6tables_outbound_established.sh -> 4.3.3.3 - ip6tables_rule_them_all.sh -> 4.3.3.4 - ip6tables_default_deny_policy.sh -> 4.3.3.1
2025-09-03 13:18:21 +02:00 · 2025-08-05 16:23:52 +02:00
parent 1926758707
commit 4be1a9d9e4
14 changed files with 819 additions and 0 deletions
--- a/bin/hardening/ip6tables_rule_them_all.sh
+++ b/bin/hardening/ip6tables_rule_them_all.sh
@@ -0,0 +1,108 @@
+#!/bin/bash
+
+# run-shellcheck
+#
+# CIS Debian Hardening
+#
+
+#
+# Ensure ip6tables firewall rules exist for all open ports (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 ip6tables firewall rules exist for all open ports"
+PACKAGE="iptables"
+
+# we are going to
+# - list listening ports
+# - list ip6tables rules using dport
+# - compare both
+
+# This function will be called if the script status is on enabled / audit mode
+audit() {
+    is_pkg_installed "$PACKAGE"
+    if [ "$FNRET" -ne 0 ]; then
+        crit "$PACKAGE is not installed"
+        return
+    fi
+
+    is_ipv6_enabled
+    if [ "$NFRET" -ne 0 ]; then
+        ok "ipv6 is not enabled"
+        return
+    fi
+
+    IPTABLES_IS_VALID=0
+    local iptables_ports_rules=""
+    local listening_ports
+    # we may have configured some custom chains in INPUT, that need to be checked too.
+    local custom_chains=""
+    local builtin_targets="ACCEPT DROP QUEUE RETURN"
+
+    for target in $($SUDO_CMD ip6tables -L INPUT | awk '{print $1}' | sed '1,2d'); do
+        if ! grep "$target" <<<"$builtin_targets" >/dev/null; then
+            custom_chains="$custom_chains $target"
+        fi
+    done
+
+    for chain in INPUT $custom_chains; do
+        # number of fields is not fixed, there may be some comments before and after
+        # ex:
+        # udp spt:68 dpt:67 /* DHCP Request */
+        # /* ssh connection */ tcp dpt:22
+        iptables_ports_rules="$iptables_ports_rules $($SUDO_CMD ip6tables -nL "$chain" | grep 'dpt:' | sed 's/^.*dpt://g' | awk '{print $1}' | sort -u)"
+    done
+    listening_ports=$($SUDO_CMD ss -tuln | awk '($5!~/%lo:/ && $5!~/127.0.0.1:/ && $5!~/\[?::1\]?:/) {split($5, a, ":"); print a[2]}' | sort -u)
+
+    for port in $listening_ports; do
+        if ! grep "$port" <<<"$iptables_ports_rules" >/dev/null; then
+            crit "$port does not have an ip6tables rule"
+            IPTABLES_IS_VALID=1
+        fi
+    done
+
+    if [ "$IPTABLES_IS_VALID" -eq 0 ]; then
+        ok "all listening ports have a corresponding rule in ufw"
+    fi
+}
+
+# This function will be called if the script status is on enabled mode
+apply() {
+    audit
+    if [ "$IPTABLES_IS_VALID" -ne 0 ]; then
+        # Debian 12 CIS marks this script as "Automated", but we wont do it
+        # How can we know if a rule should be allowed or denied ? From everywhere ? A specific range ?
+        warn "Please review the ip6tables rules and update them accordingly. We wont do it in an automated way, as we don't know if it should be allowed or denied"
+    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