Message-ID: <CA+CewVDQ_ApoHbGWMkv2bUub_f8PHwfe5Yhr4RPYPJJui2YkBg@mail.gmail.com>
Date: Fri, 14 Mar 2014 19:28:45 +0000
From: "Nicholas Lemonias." <lem.nikolas@...glemail.com>
To: R D <rd.seclists@...il.com>, full-disclosure@...ts.grok.org.uk
Subject: Re: Fwd: Google vulnerabilities with PoC

Then that also means that firewalls and IPS systems are worthless. Why
spend so much time protecting the network layers if a user can send any
file of choice to a remote network through http...

As for the uploaded files being persistent, there is evidence of that.  For
instance a remote admin could be tricked to execute some of the uploaded
files (Social Engineering).

So our report sent as part of Google's security program, should not be
treated as a non-security issue.


Thanks,


On Fri, Mar 14, 2014 at 7:23 PM, R D <rd.seclists@...il.com> wrote:

> I'm going to try to spell it out clearly.
>
> You don't have unrestricted file upload[1]. Keep in mind you're trying to
> abuse youtube, which is essentially a video file upload service. So the
> fact that you can upload files is not surprising.
> Now you're uploading non-video files. Cool. But not earth-shattering.
> They are not accessible to anyone but you, as far as I can tell, and I
> don't even think you can access the file contents on the remote server, but
> please prove me wrong on both points.
> You are still, as far as I can tell, bound by the per-file and per-account
> quota on disk occupation, so you don't have a DoS by resource exhaustion.
> You can't force server-side file path, so you don't have RFI or DoS by
> messing with the remote file system. You can't execute the files you
> uploaded, so you don't have arbitrary code execution.
>
> But you are right about what your PoC does. You bypassed a security
> control, you uploaded crap on youtube servers, and by that you exhausted
> their resources by a fraction of the quota they allow you when signing up.
> BTW, I don't think they keep invalid video files for an indefinite period
> of time in a user account, but I might be wrong.
>
> The burden of proof is still on your side as to whether or not the bug you
> found has any impact that was not already accepted by youtube allowing
> registered users to upload whatever crap they see fit as long as it is
> video. You failed to provide this proof, and please be sure the audience of
> fulldisclosure is not "attacking the researcher" but working with you to
> have a better understanding of the bug you found, even though you kinda
> acted like a fool in this thread.
>
> Please keep on searching and finding vulns, please keep on publishing
> them, and use this as a learning experience that not all bugs or control
> bypasses are security vulnerabilities.
>
> --Rob'
>
> [1] As per OWASP (https://www.owasp.org/index.php/Unrestricted_File_Upload
> ):
>
> >There are really two classes of problems here. The first is with the file
> metadata, like the path and file name. These are generally provided by the
> transport, such as HTTP multi-part encoding. This data may trick the
> application into overwriting a critical file or storing the file in a bad
> location. You must validate the metadata extremely carefully before using
> it.
>
> Your POC doesn't demonstrate that.
>
> >The other class of problem is with the file size or content. The range of
> problems here depends entirely on what the file is used for. See the
> examples below for some ideas about how files might be misused. To protect
> against this type of attack, you should analyze everything your application
> does with files and think carefully about what processing and interpreters
> are involved.
>
> Your POC kinda does that, but you didn't provide proof it's possible to
> execute what you uploaded, either using social engineering or any other
> method.
>
> Also, please don't say "verified by a couple of recognised experts
> including OWASP" unless you actually spoke with someone @owasp and she
> validated your findings.
>
>
> On Fri, Mar 14, 2014 at 7:40 PM, Nicholas Lemonias. <
> lem.nikolas@...glemail.com> wrote:
>
>> We have many PoC's including video clips. We may upload for the security
>> world to see.
>>
>> However, this is not the way to treat security vulnerabilities. Attacking
>> the researcher and bringing you friends to do aswell, won't mitigate the
>> problem.
>>
>>
>>
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>
>

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