Message-ID: <CAM2Hf5m-j3=rv6-V6M0EFGx-n7NSEH8Fb2moLCMStCMeLZSv0g@mail.gmail.com>
Date: Mon, 13 Feb 2012 08:38:10 -0800
From: Gage Bystrom <themadichib0d@...il.com>
To: adam <adam@...sy.net>, 
	"full-disclosure@...ts.grok.org.uk" <full-disclosure@...ts.grok.org.uk>
Subject: Re: Arbitrary DDoS PoC

Absolutely and that's partly my point. The methods you describe are neigh
exactly how modern general ddos techniques work, which is not how this
works.

One problem is you can't use Facebook or Google as an open proxy like
you're saying because 1.) It assumes you can force Google or Facebook to
make multiple requests for just one of your requests, else you are still
being stuck to how much you can output vs how much they can take. Just
because you can tweak how much you can send does not change the basic
principal behind this and 2.) It no longer becomes a general method because
you must abuse a particular flaw in a particular service to get it to use
its resources to flood the targets resources.

Not trying to really argue your examples, I'm just saying his script and
his "bug report" or whatever you call it is terribly ineffective as a
general method compared to pretty standard techniques like you described,
and does not abuse any implementation or protocol to be a specific flaw a
la the Apache dos bug a few months ago. It's like he's claiming he found
the new smurf attack when all the attack is a script calling curl through a
proxy, torrenting the latest distro install disk is a bigger "DoS"
technique than this.
On Feb 13, 2012 5:48 AM, "adam" <adam@...sy.net> wrote:

> I have to admit that I've only read the posts here, haven't actually
> followed the link, but in response to Gage:
>
> It entirely depends on how it's being done, specifically: what
> services/applications are being targeted and in what way. If he's proxying
> through "big" servers such as those owned by Facebook, Google, Wikipedia,
> etc: then it definitely does make a difference. You're assuming that his
> network speed would be the bottleneck, but to make that assumption, you
> first have to assume that he's actually waiting around for response data.
>
> Maybe it's too early to convey this in an understandable way, I don't
> know. An example scenario that would be effective though: imagine that you
> run a web server, also imagine that there's a resource (CPU/bandwidth)
> intensive script/page on that server. For the sake of discussion, let's
> assume that my home internet speed is 1/10 of your server. We can also
> probably assume that your server's network speed is 1/10 of Google's. If I
> can force Google's server to request that page, that automatically puts me
> at an advantage (especially if I close the connection before Google can
> send the response back to me).
>
> Even if you're correct about his particular script, the logic behind your
> response is flawed. In the above example, one could use multithreading to
> cycle requests to your server through Google, Facebook, Wikipedia, whoever.
> As soon as the request has been sent, the connection could be terminated.
> If that for some reason wouldn't work, the script could wait until one byte
> is received (e.g. the "2" in "200 OK") and close the connection then. At
> that point, the bandwidth/resources would have already been used.
>
> The bottom line is that you could easily use the above concepts (and
> likely what the OP has designed) to overpower a server/service while using
> very little resources of your own. It's all circumstantial anyway though.
> My overall point, specifics aside, is that being able to use Google or
> Facebook's resources against a target is definitely beneficial and has all
> kinds of advantages.
>
> On Mon, Feb 13, 2012 at 7:17 AM, Gage Bystrom <themadichib0d@...il.com>wrote:
>
>> Uhh...looks pretty standard boss. You aren't going to DoS a halfway
>> decent server with that using a single box. Sending your request through
>> multiple proxies does not magically increase the resource usage of the
>> target, its still your output power vs their input pipe. Sure it gives a
>> slight boost in anonymity and obfuscation but does not actually increase
>> effectiveness. It would even decrease effectiveness because you bear the
>> burden of having to send to a proxy, giving them ample time to recover from
>> a given request.
>>
>> Even if you look at it as a tactic to bypass blacklisting, you still
>> aren't going to overwhelm the server. That means you need more pawns to do
>> your bidding. This creates a bit of a problem however as then all your
>> slaves are running through a limited selection of proxies, reducing the
>> amount of threats the server needs to blacklist. The circumvention is quite
>> obvious, which is to not utilize proxies for the pawns....and rely on shear
>> numbers and/or superior resource exhaustion methods....
>>  On Feb 13, 2012 4:37 AM, "Lucas Fernando Amorim" <lf.amorim@...oo.com.br>
>> wrote:
>>
>>> With the recent wave of DDoS, a concern that was not taken is the model
>>> where the zombies were not compromised by a Trojan. In the standard
>>> modeling of DDoS attack, the machines are purchased, usually in a VPS,
>>> or are obtained through Trojans, thus forming a botnet. But the
>>> arbitrary shape doesn't need acquire a collection of computers.
>>> Programs, servers and protocols are used to arbitrarily make requests on
>>> the target. P2P programs are especially vulnerable, DNS, internet
>>> proxies, and many sites that make requests of user like Facebook or W3C,
>>> also are.
>>>
>>> Precisely I made a proof-of-concept script of 60 lines hitting most of
>>> HTTP servers on the Internet, even if they have protections likely
>>> mod_security, mod_evasive. This can be found on this link [1] at GitHub.
>>> The solution of the problem depends only on the reformulation of
>>> protocols and limitations on the number of concurrent requests and
>>> totals by proxies and programs for a given site, when exceeded returning
>>> a cached copy of the last request.
>>>
>>> [1] https://github.com/lfamorim/barrelroll
>>>
>>> Cheers,
>>> Lucas Fernando Amorim
>>> http://twitter.com/lfamorim
>>>
>>> _______________________________________________
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>>>
>>
>> _______________________________________________
>> Full-Disclosure - We believe in it.
>> Charter: http://lists.grok.org.uk/full-disclosure-charter.html
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>>
>
>

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