ossec-blacklist/blacklist.sh
2015-01-09 12:16:57 +00:00

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#!/bin/sh
# IP blacklisting script for Linux servers
# Pawel Krawczyk 2014-2015
# documentation https://github.com/kravietz/blacklist-scripts
# Emerging Threats lists offensive IPs such as botnet command servers
urls="http://rules.emergingthreats.net/fwrules/emerging-Block-IPs.txt"
# Blocklist.de collects reports from fail2ban probes, listing password brute-forces, scanners and other offenders
urls="$urls https://www.blocklist.de/downloads/export-ips_all.txt"
# badips.com, from score 2 up
urls="$urls http://www.badips.com/get/list/ssh/2"
blocklist_chain_name=blocklists
if [ -z "$(which ipset)" ]; then
echo "Cannot find ipset"
echo "Run \"apt-get install ipset\" or \"yum install ipset\""
exit 1
fi
if [ -z "$(which curl)" ]; then
echo "Cannot find curl"
echo "Run \"apt-get install curl\" or \"yum install curl\""
exit 1
fi
if [ "$(which uci)" ]; then
# we're on OpenWRT
wan_iface=$(uci get network.wan.ifname)
IN_OPT="-i $wan_iface"
INPUT=input_rule
FORWARD=forwarding_rule
COMPRESS_OPT=""
else
COMPRESS_OPT="--compressed"
INPUT=INPUT
FORWARD=FORWARD
fi
# create main blocklists chain
if ! iptables -L | grep -q "Chain ${blocklist_chain_name}"; then
iptables -N ${blocklist_chain_name}
fi
# inject references to blocklist in the beginning of input and forward chains
if ! iptables -L ${INPUT} | grep -q ${blocklist_chain_name}; then
iptables -I ${INPUT} 1 ${IN_OPT} -j ${blocklist_chain_name}
fi
if ! iptables -L ${FORWARD} | grep -q ${blocklist_chain_name}; then
iptables -I ${FORWARD} 1 ${IN_OPT} -j ${blocklist_chain_name}
fi
# flush the chain referencing blacklists, they will be restored in a second
iptables -F ${blocklist_chain_name}
# create the "manual" blacklist set
set_name="manual-blacklist"
if ! ipset list | grep -q "Name: ${set_name}"; then
ipset create "${set_name}" hash:net
fi
iptables -A ${blocklist_chain_name} -m set --match-set "${set_name}" src,dst -m limit --limit 10/minute -j LOG --log-prefix "BLOCK ${set_name} "
iptables -A ${blocklist_chain_name} -m set --match-set "${set_name}" src,dst -j DROP
# now process the dynamic blacklists
for url in $urls; do
# initialize temp files
unsorted_blocklist=$(mktemp)
sorted_blocklist=$(mktemp)
new_set_file=$(mktemp)
# download the blocklist
set_name=$(echo "$url" | awk -F/ '{print $3;}') # set name is derived from source URL hostname
curl -s ${COMPRESS_OPT} -k "$url" >"${unsorted_blocklist}"
sort -u <"${unsorted_blocklist}" | egrep "^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$" >"${sorted_blocklist}"
# calculate performance parameters for the new set
tmp_set_name="tmp_${RANDOM}"
new_list_size=$(wc -l "${sorted_blocklist}" | awk '{print $1;}' )
hash_size=$(expr $new_list_size / 2)
if ! ipset -q list ${set_name} >/dev/null ; then
ipset create ${set_name} hash:net family inet
fi
# start writing new set file
echo "create ${tmp_set_name} hash:net family inet hashsize ${hash_size} maxelem ${new_list_size}" >>"${new_set_file}"
# convert list of IPs to ipset statements
while read line; do
echo "add ${tmp_set_name} ${line}" >>"${new_set_file}"
done <"$sorted_blocklist"
# replace old set with the new, temp one - this guarantees an atomic update
echo "swap ${tmp_set_name} ${set_name}" >>"${new_set_file}"
# clear old set (now under temp name)
echo "destroy ${tmp_set_name}" >>"${new_set_file}"
# actually execute the set update
ipset -! -q restore < "${new_set_file}"
iptables -A ${blocklist_chain_name} -m set --match-set "${set_name}" src,dst -m limit --limit 10/minute -j LOG --log-prefix "BLOCK ${set_name} "
iptables -A ${blocklist_chain_name} -m set --match-set "${set_name}" src,dst -j DROP
# clean up temp files
rm "${unsorted_blocklist}" "${sorted_blocklist}" "${new_set_file}"
done