ansible-personal/roles/common/files/update-abusech-nftables.sh
Alan Orth 8dd7663b3c
roles/common: Use Abuse.ch's SSL Blacklist in nftables
This adds Abuse.sh's list of IPs using blacklisted SSL certificates
to nftables. These IPs are high confidence indicators of compromise
and we should not route them. The list is updated daily by a systemd
timer.

See: https://sslbl.abuse.ch/blacklist/
2021-07-29 10:16:00 +03:00

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#!/usr/bin/env bash
#
# update-abuseipdb-nftables.sh v0.0.1
#
# Download IP addresses seen using a blacklisted SSL certificate and load them
# into nftables sets. As of 2021-07-28 these appear to only be IPv4.
#
# See: https://sslbl.abuse.ch/blacklist
#
# Copyright (C) 2021 Alan Orth
#
# SPDX-License-Identifier: GPL-3.0-only
# Exit on first error
set -o errexit
abusech_ipv4_set_path=/etc/nftables/abusech-ipv4.nft
abusech_list_temp=$(mktemp)
echo "Downloading Abuse.sh SSL Blacklist IPs"
abusech_response=$(curl -s -G -w "%{http_code}\n" https://sslbl.abuse.ch/blacklist/sslipblacklist.txt --output "$abusech_list_temp")
if [[ $abusech_response -ne 200 ]]; then
echo "Abuse.ch responded: HTTP $abusech_response"
exit 1
fi
if [[ -f "$abusech_list_temp" ]]; then
echo "Processing IPv4 list"
abusech_ipv4_list_temp=$(mktemp)
abusech_ipv4_set_temp=$(mktemp)
# Remove comments, DOS carriage returns, and IPv6 addresses (even though
# Abuse.ch seems to only have IPv4 addresses, let's not break our shit on
# that assumption some time down the line).
sed -e '/#/d' -e 's/
//' -e '/:/d' "$abusech_list_temp" > "$abusech_ipv4_list_temp"
echo "Building abusech-ipv4 set"
cat << NFT_HEAD > "$abusech_ipv4_set_temp"
#!/usr/sbin/nft -f
define ABUSECH_IPV4 = {
NFT_HEAD
while read -r network; do
# nftables doesn't mind if the last element in the set has a trailing
# comma so we don't need to do anything special here.
echo "$network," >> "$abusech_ipv4_set_temp"
done < $abusech_ipv4_list_temp
echo "}" >> "$abusech_ipv4_set_temp"
install -m 0600 "$abusech_ipv4_set_temp" "$abusech_ipv4_set_path"
rm -f "$abusech_list_temp" "$abusech_ipv4_list_temp" "$abusech_ipv4_set_temp"
fi
echo "Reloading nftables"
# The abusech nftables sets are included by nftables.conf
/usr/sbin/nft -f /etc/nftables.conf