Re: Evading Client-Certificate Authentication

["Kevin Vanhaelen" <blowfish448 () hotmail com>]

indeed it is during a blind penetration test that I found this web server.
In a next phase the customer will provide me with a temporary client
certificate
but I wanted to know how far I could get without. To simulate a
non-customer/
employee connecting to the server in question.

Thanks,

~kevin

----- Original Message ----- 
From: "Imre Kertesz" <ikertesz () fastq com>
To: <pen-test () securityfocus com>; <webappsec () securityfocus com>
Sent: Thursday, April 01, 2004 1:58 AM
Subject: Re: Evading Client-Certificate Authentication


> Im not one to argue semantics, but "stumbling" upon a web server during
> a "sanctioned" penetration test doesn't happen unless the penetration
> test is blind .. or the customer forgot to set you up with a client
> certificate .. or the web server that you stumbled upon isn't within the
> scope of your sanctioned assessment.  In all cases but the latter, the
> customer needs to generate a client certificate for you. They are
> probably running their own CA, which you may need to visit to generate a
> certificate request. The trick is to get a certificate that is
> EXPORTABLE so that you can fux0r it with openssl into PEM format that
> stunnel can use and viola - instant client certificate proxy.  Once you
> have this client certificate / stunnel proxy, you might have to do some
> local DNS foo to make sure that the application recognizes your stunnel
> host as a legitimate target, but it should work fine.
>
> -I
>
> Kevin Vanhaelen wrote:
>
> > Hi to all,
> >
> > whilst in the middle of a Penetration Test I stumbled on a web server
only
> > serving SSL and demanding the client to present
> > a certificate to identify himself.
> > I tried to nikto it with sslproxy and browse the site thru paros both
with a
> > temporary Verisign personal certificate.
> > No such luck, the server keeps bouncing me off. Even vulnerability
scanners
> > like Nessus and Retina don't get passed
> > the port-scan portion.
> >
> > Does anyone have an idea to further assess this server? Am I looking at a
> > mission impossible here maybe?
> >
> > Thanks,
> >
> > ~kevin
>
> -- 
>
> -· · ···- · ·-· ·--· · - ·- -··· ··- ·-· -· ·· -· --· -·· --- --·
> "If you sit quietly at the edge of a river, eventually
> you will see the bodies of your enemies float by"
> -A maxim of patience, author unknown
>
> Imre Kertesz
> PGP ID: 0xA5DD6F44