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Re: reduction of brute force log
From: "Matthijs van Otterdijk" <thotter () gmail com>
Date: Tue, 28 Feb 2006 17:59:41 +0100

Hey, I didn't write it, I just copied a link :P. Maybe the author likes to
be pinged? Dunno what those ports are...

On 2/28/06, Bob Radvanovsky <rsradvan () unixworks net> wrote:

I am going to test these rules out -- this looks REALLy good!  But...I've
got just ONE question: why on Earth would you permit ICMP???

And what significances are ports 50, 51, 1599, 1600 and 1601?  443 and 80
are HTTP-S and HTTP (respectively), 123 is NTP -- I realize that, but what
are these others ports used for?

-r

*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:RH-Firewall-1-INPUT - [0:0]
-A INPUT -j RH-Firewall-1-INPUT
-A FORWARD -j RH-Firewall-1-INPUT
-A RH-Firewall-1-INPUT -i lo -j ACCEPT
-A RH-Firewall-1-INPUT -s 10.0.0.0/24 -j ACCEPT
-A RH-Firewall-1-INPUT -p icmp --icmp-type any -j ACCEPT
-A RH-Firewall-1-INPUT -p 50 -j ACCEPT
-A RH-Firewall-1-INPUT -p 51 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 22 -m
recent --rcheck --name SSH -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j
ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m udp -p udp --dport 123 -j
ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 443 -j
ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 1599 -m
recent --name SSH --remove -j DROP
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 1600 -m
recent --name SSH --set -j DROP
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 1601 -m
recent --name SSH --remove -j DROP
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited
COMMIT


----- Original Message -----
From: Matthijs van Otterdijk [mailto:thotter () gmail com]
To: full-disclosure () lists grok org uk
Subject: Re: [Full-disclosure] reduction of brute force login attempts via
SSH  through iptables --hashlimit


I haven't tried this myself, and I don't know if it is already
suggested,
but this should stop all the pesky scriptkiddies from filling up your
logs.
Might prove to be a better solution, who knows:
http://aplawrence.com/Security/sshloginattack.html

Matthijs



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