linux-kernel - Re: How would I do this? (expert tricks) OT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Pine.LNX.4.64.0706191919280.5731@fbirervta.pbzchgretzou.qr>
Date:	Tue, 19 Jun 2007 19:28:25 +0200 (CEST)
From:	Jan Engelhardt <jengelh@...putergmbh.de>
To:	Marc Perkel <mperkel@...oo.com>
cc:	linux-kernel@...r.kernel.org
Subject: Re: How would I do this? (expert tricks) OT

On Jun 19 2007 10:14, Marc Perkel wrote:
>> 
>> tcpdump -lni any port 25
>> iptables -p tcp --dport 25 -j NFQUEUE
>> ...
>> 
>
>Thanks Jan, but I'm not sure it answers my question.

There's more than one way to do it.

One is...
	tcpdump -lni eth0 tcp [extra operands to match SYN packets] |
	myprogram

a longer one is to write your own netfilter userspace program
that receives the TCP SYNs (by means of -j NFQUEUE) and does
take action.

Another one is to use -j LOG and let your program parse
down /var/log/firewall. Like

	iptables -A INPUT -p tcp --dport 25 --syn -j LOG --log-prefix "[evil]"
	tail -f /var/log/firewall | grep '^\[evil\]' | myscript

myscript:
#!/usr/bin/perl

while (defined(my $line = <>)) {
	my($ip) = ($line =~ /SRC=(\S+)/);
	# Do something
}

>I want to run a script every time a connection attempt is made in real time

The scripts runs constantly, preferably.

>with the IP address as a parameter to the script. How would I do that? Suppose
>my script is:
>
>iplog <ipaddress>
>
>
>
>
>       
>____________________________________________________________________________________
>Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news, photos & more. 
>http://mobile.yahoo.com/go?refer=1GNXIC
>

	Jan
-- 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/