#!/bin/bash
# Variaveis
# -------------------------------------------------------
iptables=/sbin/iptables
IF_EXTERNA=ppp0
IF_INTERNA=eth0
echo "Variaveis OK!"
# Ativa modulos
# -------------------------------------------------------
/sbin/modprobe iptable_nat
/sbin/modprobe ip_conntrack
/sbin/modprobe ip_conntrack_ftp
/sbin/modprobe ip_nat_ftp
/sbin/modprobe ipt_LOG
/sbin/modprobe ipt_REJECT
/sbin/modprobe ipt_MASQUERADE
echo "Carga dos Modulos OK!"
# Ativa roteamento no kernel
# -------------------------------------------------------
echo "1" > /proc/sys/net/ipv4/ip_forward
echo "Roteamento OK!"
# Protecao contra IP spoofing
# -------------------------------------------------------
echo "1" > /proc/sys/net/ipv4/conf/all/rp_filter
echo "Protecao contra IP Spoofing OK!"
# Zera regras
# -------------------------------------------------------
$iptables -F
$iptables -X
$iptables -F -t nat
$iptables -X -t nat
$iptables -F -t mangle
$iptables -X -t mangle
echo "Flush das regras OK!"
# Determina a politica padrao
# -------------------------------------------------------
$iptables -P INPUT DROP
$iptables -P OUTPUT DROP
$iptables -P FORWARD DROP
echo "Politica padrao OK!"
# Dropa pacotes TCP indesejaveis
# -------------------------------------------------------
$iptables -A FORWARD -p tcp ! --syn -m state --state NEW -j LOG --log-level 6 --log-prefix "FIREWALL: NEW sem syn: "
$iptables -A FORWARD -p tcp ! --syn -m state --state NEW -j DROP
# Dropa pacotes mal formados
# -------------------------------------------------------
#$iptables -A INPUT -i $IF_EXTERNA -m unclean -j LOG --log-level 6 --log-prefix "FIREWALL: Pac. Mal Formado: "
#$iptables -A INPUT -i $IF_EXTERNA -m unclean -j DROP
# Protecao contra worms
# -------------------------------------------------------
$iptables -A FORWARD -p tcp --dport 135 -i $IF_INTERNA -j REJECT
# Aceita os pacotes que realmente devem entrar
# -------------------------------------------------------
$iptables -A INPUT -i ! $IF_EXTERNA -j ACCEPT
$iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
$iptables -A OUTPUT -m state --state ESTABLISHED,RELATED,NEW -j ACCEPT
$iptables -A FORWARD -m state --state ESTABLISHED,RELATED,NEW -j ACCEPT
echo "Pacotes IN/OUT OK!"
# Protecao contra trinoo
# -------------------------------------------------------
$iptables -N TRINOO
$iptables -A TRINOO -m limit --limit 15/m -j LOG --log-level 6 --log-prefix "FIREWALL: trinoo: "
$iptables -A TRINOO -j DROP
$iptables -A INPUT -p tcp -i $IF_EXTERNA --dport 27444 -j TRINOO
$iptables -A INPUT -p tcp -i $IF_EXTERNA --dport 27665 -j TRINOO
$iptables -A INPUT -p tcp -i $IF_EXTERNA --dport 31335 -j TRINOO
$iptables -A INPUT -p tcp -i $IF_EXTERNA --dport 34555 -j TRINOO
$iptables -A INPUT -p tcp -i $IF_EXTERNA --dport 35555 -j TRINOO
echo "Protecao contra TRINOO OK!"
# Protecao contra tronjans
# -------------------------------------------------------
$iptables -N TROJAN
$iptables -A TROJAN -m limit --limit 15/m -j LOG --log-level 6 --log-prefix "FIREWALL: trojan: "
$iptables -A TROJAN -j DROP
$iptables -A INPUT -p tcp -i $IF_EXTERNA --dport 666 -j TROJAN
$iptables -A INPUT -p tcp -i $IF_EXTERNA --dport 666 -j TROJAN
$iptables -A INPUT -p tcp -i $IF_EXTERNA --dport 4000 -j TROJAN
$iptables -A INPUT -p tcp -i $IF_EXTERNA --dport 6000 -j TROJAN
$iptables -A INPUT -p tcp -i $IF_EXTERNA --dport 6006 -j TROJAN
$iptables -A INPUT -p tcp -i $IF_EXTERNA --dport 16660 -j TROJAN
echo "Protecao contra TROJANS OK!"
# Protecao contra syn-flood
# -------------------------------------------------------
$iptables -A FORWARD -p tcp --syn -m limit --limit 2/s -j ACCEPT
$iptables -A FORWARD -p tcp -j DROP
echo "Protecao contra SYN-FLOOD OK!"
# Protecao contra ping da morte
# -------------------------------------------------------
$iptables -A FORWARD -p icmp --icmp-type echo-request -m limit --limit 1/s -j ACCEPT
$iptables -A FORWARD -p icmp -j DROP
echo "Protecao contra Ping-Of-Death OK!"
# Protecao contra port scanners
# -------------------------------------------------------
$iptables -N SCANNER
$iptables -A SCANNER -m limit --limit 15/m -j LOG --log-level 6 --log-prefix "FIREWALL: port scanner: "
$iptables -A SCANNER -j DROP
$iptables -A INPUT -p tcp --tcp-flags ALL FIN,URG,PSH -i $IF_EXTERNA -j SCANNER
$iptables -A INPUT -p tcp --tcp-flags ALL NONE -i $IF_EXTERNA -j SCANNER
$iptables -A INPUT -p tcp --tcp-flags ALL ALL -i $IF_EXTERNA -j SCANNER
$iptables -A INPUT -p tcp --tcp-flags ALL FIN,SYN -i $IF_EXTERNA -j SCANNER
$iptables -A INPUT -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -i $IF_EXTERNA -j SCANNER
$iptables -A INPUT -p tcp --tcp-flags SYN,RST SYN,RST -i $IF_EXTERNA -j SCANNER
$iptables -A INPUT -p tcp --tcp-flags SYN,FIN SYN,FIN -i $IF_EXTERNA -j SCANNER
echo "Protecao contra Port-Scanners OK!"
# Loga tentativa de acesso a determinadas portas
# -------------------------------------------------------
$iptables -A INPUT -p tcp --dport 21 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: ftp: "
$iptables -A INPUT -p tcp --dport 22 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: ssh: "
$iptables -A INPUT -p tcp --dport 23 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: telnet: "
$iptables -A INPUT -p tcp --dport 25 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: smtp: "
$iptables -A INPUT -p tcp --dport 80 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: http: "
$iptables -A INPUT -p tcp --dport 110 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: pop3: "
$iptables -A INPUT -p udp --dport 111 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: rpc: "
$iptables -A INPUT -p tcp --dport 113 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: identd: "
$iptables -A INPUT -p tcp --dport 137:139 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: samba: "
$iptables -A INPUT -p udp --dport 137:139 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: samba: "
$iptables -A INPUT -p tcp --dport 143 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: IMAP: "
$iptables -A INPUT -p tcp --dport 161:162 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: snmp: "
$iptables -A INPUT -p tcp --dport 6667:6668 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: irc: "
$iptables -A INPUT -p tcp --dport 3128 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: squid: "
$iptables -A INPUT -p tcp --dport 8080 -i $IF_EXTERNA -j LOG --log-level 6 --log-prefix "FIREWALL: squid: "
echo "Logs OK!"
# Habilitando acesso a determinadas portas
# --------------------------------------------------------
$iptables -A INPUT -p tcp --dport 21 -i $IF_EXTERNA -j ACCEPT
$iptables -A INPUT -p tcp --dport 22 -i $IF_EXTERNA -j ACCEPT
$iptables -A INPUT -p tcp --dport 25 -i $IF_EXTERNA -j ACCEPT
$iptables -A INPUT -p udp --dport 53 -i $IF_EXTERNA -j ACCEPT
$iptables -A INPUT -p tcp --dport 80 -i $IF_EXTERNA -j ACCEPT
$iptables -A INPUT -p tcp --dport 110 -i $IF_EXTERNA -j ACCEPT
$iptables -A INPUT -p tcp --dport 143 -i $IF_EXTERNA -j ACCEPT
$iptables -A INPUT -p tcp --dport 443 -i $IF_EXTERNA -j ACCEPT
echo "Acesso a determinadas portas OK!"
# Proxy transparente
# -------------------------------------------------------
$iptables -t nat -A PREROUTING -i $IF_INTERNA -p tcp --dport 80 -j REDIRECT --to-port 8080
$iptables -t nat -A PREROUTING -i $IF_INTERNA -p tcp --dport 3128 -j REDIRECT --to-port 8080