firewall: add more pscan matches and filter INVALID conntrack packages.

This commit is contained in:
Arne Fitzenreiter
2014-07-29 21:57:07 +02:00
parent 4e9a2b5732
commit dccbf1bf4e

View File

@@ -64,16 +64,20 @@ iptables_init() {
iptables -A BADTCP -i lo -j RETURN
# Disallow packets frequently used by port-scanners
# nmap xmas
iptables -A BADTCP -p tcp --tcp-flags ALL FIN,URG,PSH -j PSCAN
# Null
iptables -A BADTCP -p tcp --tcp-flags ALL NONE -j PSCAN
# FIN
# NMAP FIN/URG/PSH (XMAS scan)
iptables -A BADTCP -p tcp --tcp-flags ALL FIN,URG,PSH -j PSCAN
# SYN/RST/ACK/FIN/URG
iptables -A BADTCP -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j PSCAN
# ALL/ALL
iptables -A BADTCP -p tcp --tcp-flags ALL ALL -j PSCAN
# FIN Stealth
iptables -A BADTCP -p tcp --tcp-flags ALL FIN -j PSCAN
# SYN/RST (also catches xmas variants that set SYN+RST+...)
iptables -A BADTCP -p tcp --tcp-flags SYN,RST SYN,RST -j PSCAN
# SYN/FIN (QueSO or nmap OS probe)
iptables -A BADTCP -p tcp --tcp-flags SYN,FIN SYN,FIN -j PSCAN
# Null
iptables -A BADTCP -p tcp --tcp-flags ALL NONE -j PSCAN
# NEW TCP without SYN
iptables -A BADTCP -p tcp ! --syn -m conntrack --ctstate NEW -j NEWNOTSYN
@@ -83,6 +87,7 @@ iptables_init() {
# Connection tracking chain
iptables -N CONNTRACK
iptables -A CONNTRACK -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -A CONNTRACK -m conntrack --ctstate INVALID -j DROP
# Fix for braindead ISP's
iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu