110 lines
4.3 KiB
Bash
110 lines
4.3 KiB
Bash
#!/bin/bash
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IPT="/sbin/iptables"
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PUB_IFS="ens33"
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if [ $# -lt 1 ]; then
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echo "Must be set to greater than or equal to a public network interface. "
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echo "usage: $0 eth0, or $0 eth0 eth1"
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exit 1
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else
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PUB_IFS="$@"
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echo "Public interface is $PUB_IFS"
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fi
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echo "Starting IPv4 Wall..."
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$IPT -F
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$IPT -X
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$IPT -t nat -F
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$IPT -t nat -X
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$IPT -t mangle -F
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$IPT -t mangle -X
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$IPT -N LOGDROP
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modprobe ip_conntrack
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#unlimited
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$IPT -A INPUT -i lo -j ACCEPT
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$IPT -A OUTPUT -o lo -j ACCEPT
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# DROP all incomming traffic
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$IPT -P INPUT DROP
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$IPT -P OUTPUT DROP
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$IPT -P FORWARD DROP
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$IPT -A INPUT -i lo -j ACCEPT
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$IPT -A OUTPUT -o lo -j ACCEPT
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$IPT -A INPUT -s 127.0.0.0/8 -j DROP
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$IPT -A OUTPUT -p tcp -m state --state NEW,ESTABLISHED -j ACCEPT
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$IPT -A OUTPUT -p udp -m state --state NEW,ESTABLISHED -j ACCEPT
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$IPT -A OUTPUT -p icmp -m state --state NEW,ESTABLISHED -j ACCEPT
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$IPT -A INPUT -p tcp -m state --state ESTABLISHED -j ACCEPT
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$IPT -A INPUT -p udp -m state --state ESTABLISHED -j ACCEPT
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$IPT -A INPUT -p icmp -m state --state ESTABLISHED -j ACCEPT
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$IPT -A INPUT -p icmp -m state --state RELATED -j ACCEPT
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$IPT -A INPUT -m limit --limit 3/min -j LOG --log-prefix "SFW2-IN-ILL-TARGET " --log-tcp-options --log-ip-options
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$IPT -A FORWARD -m physdev --physdev-is-bridged -j ACCEPT
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$IPT -A FORWARD -m limit --limit 3/min -j LOG --log-prefix "SFW2-FWD-ILL-ROUTING " --log-tcp-options --log-ip-options
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for PUB_IF in $PUB_IFS
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do
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# sync
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$IPT -A INPUT -i ${PUB_IF} -p tcp ! --syn -m state --state NEW -m limit --limit 5/m --limit-burst 7 -j LOG --log-level 4 --log-prefix "Drop Syn"
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$IPT -A INPUT -i ${PUB_IF} -p tcp ! --syn -m state --state NEW -j DROP
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# Fragments
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$IPT -A INPUT -i ${PUB_IF} -f -m limit --limit 5/m --limit-burst 7 -j LOG --log-level 4 --log-prefix "Fragments Packets"
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$IPT -A INPUT -i ${PUB_IF} -f -j DROP
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# block bad stuff
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$IPT -A INPUT -i ${PUB_IF} -p tcp --tcp-flags ALL FIN,URG,PSH -j DROP
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$IPT -A INPUT -i ${PUB_IF} -p tcp --tcp-flags ALL ALL -j DROP
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$IPT -A INPUT -i ${PUB_IF} -p tcp --tcp-flags ALL NONE -m limit --limit 5/m --limit-burst 7 -j LOG --log-level 4 --log-prefix "NULL Packets"
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$IPT -A INPUT -i ${PUB_IF} -p tcp --tcp-flags ALL NONE -j DROP # NULL packets
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$IPT -A INPUT -i ${PUB_IF} -p tcp --tcp-flags SYN,RST SYN,RST -j DROP
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$IPT -A INPUT -i ${PUB_IF} -p tcp --tcp-flags SYN,FIN SYN,FIN -m limit --limit 5/m --limit-burst 7 -j LOG --log-level 4 --log-prefix "XMAS Packets"
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$IPT -A INPUT -i ${PUB_IF} -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP #XMAS
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$IPT -A INPUT -i ${PUB_IF} -p tcp --tcp-flags FIN,ACK FIN -m limit --limit 5/m --limit-burst 7 -j LOG --log-level 4 --log-prefix "Fin Packets Scan"
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$IPT -A INPUT -i ${PUB_IF} -p tcp --tcp-flags FIN,ACK FIN -j DROP # FIN packet scans
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$IPT -A INPUT -i ${PUB_IF} -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j DROP
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# No smb/windows sharing packets - too much logging
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$IPT -A INPUT -p tcp -i ${PUB_IF} --dport 137:139 -j REJECT
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$IPT -A INPUT -p udp -i ${PUB_IF} --dport 137:139 -j REJECT
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$IPT -I INPUT -p tcp --dport 22 -i ${PUB_IF} -m state --state NEW -m recent --set
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$IPT -I INPUT -p tcp --dport 22 -i ${PUB_IF} -m state --state NEW -m recent --update --seconds 60 --hitcount 4 -j LOGDROP
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done
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# Allow full outgoing connection but no incomming stuff
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$IPT -A INPUT -p icmp -m icmp --icmp-type 4 -j ACCEPT
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$IPT -A OUTPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT
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# allow ssh/ntp/dhclint/http/https only
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$IPT -A INPUT -p tcp --dport 22 -m state --state NEW -j ACCEPT
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$IPT -A INPUT -p udp --dport 123 -m state --state NEW -j ACCEPT
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$IPT -A INPUT -p udp --dport 68 -m state --state NEW -j ACCEPT
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# $IPT -A INPUT -p tcp --dport 80 -m state --state NEW -j ACCEPT
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# $IPT -A INPUT -p tcp --dport 443 -m state --state NEW -j ACCEPT
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# allow incoming ICMP ping pong stuff
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$IPT -A INPUT -p icmp --icmp-type 8 -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT
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$IPT -A OUTPUT -p icmp --icmp-type 0 -m state --state ESTABLISHED,RELATED -j ACCEPT
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# prevent ssh brute force attack
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$IPT -A LOGDROP -j LOG
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$IPT -A LOGDROP -j DROP
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# Log everything else
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# *** Required for psad ****
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$IPT -A INPUT -j LOG
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$IPT -A FORWARD -j LOG
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$IPT -A INPUT -j DROP
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exit 0
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