From: Julien Vehent <julien@linuxwall.info>
To: Pierre LEBRECH <pierre.lebrech@laposte.net>
Cc: netfilter@vger.kernel.org
Subject: Re: libpcap (tcpdump) and netfilter (iptables)
Date: Wed, 29 Oct 2008 15:00:55 +0100 [thread overview]
Message-ID: <6a7a31ab262da35cf57c6c465226e977@localhost> (raw)
In-Reply-To: <49086324.9060900@laposte.net>
Hi,
On Wed, 29 Oct 2008 14:20:36 +0100, Pierre LEBRECH
<pierre.lebrech@laposte.net> wrote:
> Hi,
>
> It seems that even if I drop some INPUT packets with iptables, tcpdump
> still sees these packets arriving on the ethernet interface.
>
> Could anybody explain me a bit about this?
The pcap driver catch the packet before it's processed by netfilter.
This is a known issue that has even been used in a rootkit PoC to
communicate with the rootkit before the firewall drops the packet.
>
> Thanks
> --
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>
Regards,
Julien
--
www.linuxwall.info
next prev parent reply other threads:[~2008-10-29 14:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-29 13:20 libpcap (tcpdump) and netfilter (iptables) Pierre LEBRECH
2008-10-29 13:56 ` Gáspár Lajos
2008-10-29 13:56 ` Gáspár Lajos
2008-10-29 14:00 ` Julien Vehent [this message]
2008-10-29 15:11 ` Thomas Jacob
2008-10-29 16:02 ` Julien Vehent
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