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From: Eric Marchionni <mailing-lists@gmx.ch>
To: Cedric Blancher <blancher@cartel-securite.fr>
Cc: netfilter@lists.netfilter.org
Subject: Re: deny cgi scanner
Date: Tue, 01 Apr 2003 21:43:33 +0200	[thread overview]
Message-ID: <3E89EBE5.5090804@gmx.ch> (raw)
In-Reply-To: <1049219263.4784.14.camel@elendil.intranet.cartel-securite.net>

thx a lot cedric and jesper!

Cedric Blancher wrote:
> Le mar 01/04/2003 à 19:34, Eric Marchionni a écrit :
> 
>>does anybody know how to drop packets with
>>destination-port 80 after a limit of connections
>>has been reached?
>>i'd like to deny access for the attacker as soon
>>as a cgi-scan has been detected.
> 
> 
> | # limit the nr of parallel http requests to 16 per class C sized
> | # network (24 bit netmask)
> | iptables -p tcp --syn --dport 80 -m iplimit --iplimit-above 16		\
> |	--iplimit-mask 24 -j REJECT
> 
> I think it exactly fits your needs ;)

this sounds already pretty good!
as far as i understand this will result in a slowdowned scan.
if somehow possible i'd like to abort the scan at all. like
denying any connection from the attackers ip for about 1 minute 
or so...
(i know it's dangerous if someone begins spoofing google-ip or
my dns-server-ip with a cronjob, but this would only affect the
web-server...)

else i'll use iplimit ;-D

-eric



  reply	other threads:[~2003-04-01 19:43 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-04-01 17:34 deny cgi scanner Eric Marchionni
2003-04-01 17:47 ` Cedric Blancher
2003-04-01 19:43   ` Eric Marchionni [this message]
2003-04-01 20:06     ` Stephen Frost
2003-04-01 23:23       ` Arnt Karlsen
2003-04-02 12:54         ` Stephen Frost
2003-04-02 19:32           ` Arnt Karlsen
2003-04-01 18:17 ` Jesper Lund

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