82 lines
3.0 KiB
Bash
82 lines
3.0 KiB
Bash
#!/bin/sh
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# IP blacklisting script for Linux servers
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# Pawel Krawczyk https://keybase.io/kravietz
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#
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# This script should be installed as /etc/cron.daily/blacklist
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# Emerging Threats lists offensive IPs such as botnet command servers
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urls="http://rules.emergingthreats.net/fwrules/emerging-Block-IPs.txt"
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# Blocklist.de collects reports from fail2ban probes, listing password brute-forces, scanners and other offenders
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urls="$urls https://www.blocklist.de/downloads/export-ips_all.txt"
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blocklist_chain_name=blocklists
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if [ -z "$(which ipset)" ]; then
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echo "Cannot find ipset"
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echo "Run \"apt-get install ipset\" or \"yum install ipset\""
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exit 1
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fi
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if [ -z "$(which curl)" ]; then
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echo "Cannot find curl"
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echo "Run \"apt-get install curl\" or \"yum install curl\""
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exit 1
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fi
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# create main blocklists chain
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if ! iptables -L | grep -q "Chain ${blocklist_chain_name}"; then
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iptables -N ${blocklist_chain_name}
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fi
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# inject references to blocklist in the beginning of input and forward chains
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if ! iptables -L INPUT|grep -q ${blocklist_chain_name}; then
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iptables -I INPUT 1 -m state --state NEW,RELATED -j ${blocklist_chain_name}
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fi
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if ! iptables -L FORWARD|grep -q ${blocklist_chain_name}; then
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iptables -I FORWARD 1 -m state --state NEW,RELATED -j ${blocklist_chain_name}
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fi
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iptables -F ${blocklist_chain_name}
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for url in $urls; do
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# initialize temp files
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unsorted_blocklist=$(mktemp)
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sorted_blocklist=$(mktemp)
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new_set_file=$(mktemp)
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# download the blocklist
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set_name=$(basename $url)
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curl -s --compressed -k "$url" >"${unsorted_blocklist}"
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sort -u <"${unsorted_blocklist}" | egrep "^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$" >"${sorted_blocklist}"
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# calculate performance parameters for the new set
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tmp_set_name="${set_name}_tmp"
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new_list_size=$(wc -l "${sorted_blocklist}" | awk '{print $1;}' )
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hash_size=$(expr $new_list_size / 2)
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# start writing new set file
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echo "create ${set_name} hash:net family inet" >>"${new_set_file}"
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echo "create ${tmp_set_name} hash:net family inet hashsize ${hash_size} maxelem ${new_list_size}" >>"${new_set_file}"
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# convert list of IPs to ipset statements
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while read line; do
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echo "add ${tmp_set_name} ${line}" >>"${new_set_file}"
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done <"$sorted_blocklist"
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echo "swap ${tmp_set_name} ${set_name}" >>"${new_set_file}" # insert new blocklist into the old set
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echo "destroy ${tmp_set_name}" >>"${new_set_file}" # remove old set
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# actually execute the set update
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ipset restore < "${new_set_file}"
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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} "
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iptables -A ${blocklist_chain_name} -m set --match-set "${set_name}" src,dst -j DROP
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# clean up temp files
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rm "${unsorted_blocklist}" "${sorted_blocklist}" "${new_set_file}"
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done
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