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Re: [Full-disclosure] SSH brute force blocking tool

Subject: Re: [Full-disclosure] SSH brute force blocking tool
Date: Mon, 27 Nov 2006 21:38:37 +0000
On Mon, Nov 27, 2006 at 04:27:24PM -0500, J. Oquendo wrote:
Tavis Ormandy wrote:

I'm not sure what you mean by modification, I simply subsituted the name
for the logfile I use.

Thanks, Tavis.

 
So for the third time now. Explain to me how I am backdooring someone's 
system.

J, Please calm down. You have made a programming error in your script
that attempts to eliminate the minor `log noise` from incorrect ssh
logins with a script that can be subverted to execute arbitrary shell
commands.



[root@localhost include]# uname -a
Linux int-mrkt 2.6.18-1.2200.fc5 #1 Sat Oct 14 16:59:26 EDT 2006 i686 
i686 i386 GNU/Linux
[root@localhost include]# awk '/error retrieving/{getline;print $13}' 
/var/log/secure|sort -ru
222.171.20.252
211.137.74.58

My logs parse out addresses not named and there is no redirection going 
on.

Yes, but you assume a fixed format of the log entries. This is not the
case. The string "error retrieving" is easily placed in the log by
setting it as your username and attempting to login. You also assume
that the multiple log entries generated by a failed login are logged
atomically (ie, no other log entries will appear between these two
entries), this is also not the case.

If you want to say "Hey... It should be written as such" then gladly 
do so. But posting "hey you're backdooring the planet" like a jackass is 
moronic.

J, you asked people to install your "security tool" which contacts you
with enough information to find out who installed it and where, and
contains several rather obvious security flaws. If I mistook stupidity
for malice, I apologise.

Line by line on my machines it does what it needs to do and it 
does so just fine.

This is because your logs dont contain any entries specially crafted by
an attacker to subvert your machine. I'm sure some members of the list
are already attempting this on your web server, so you can check your
logs for examples.

Did you see any notes of Gentoo on the comments? I
didn't because I don't use it, never have, don't care to. So if it does 
something different on Gentoo, let's use the brain for a moment... "Gee 
this works horrible on Gentoo. The author is a shitty writer... I think 
I should let him know" as opposed to "Oh my gawd he's backdooring you".

It's a standard format J, my log entries look identical to yours. It has
nothing to do with Gentoo.

Thanks, Tavis.

-- 
-------------------------------------
taviso@sdf.lonestar.org | finger me for my pgp key.
-------------------------------------------------------

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