[OWASP_PHPSEC] [Offtopic] Decrypting information out of an image

Shivam Dixit shivamd001 at gmail.com
Fri Oct 4 14:09:30 UTC 2013


Thank you guys ! Maarten's and abhishek's method is definitely better.


On Fri, Oct 4, 2013 at 7:16 PM, Abhishek Das <das.abhshk at gmail.com> wrote:

> +1 to Maarten's method. It's visible even if you tilt your screen a bit
> and see. All it needs is a bit of in-browser -webkit-filter tweaking or
> levels in gimp adjustment.
>
>
> On Fri, Oct 4, 2013 at 7:13 PM, Maarten Hoogveld <m.hoogveld at elevate.nl>wrote:
>
>> I found the same thing in a different way actually. I just played around
>> with the color-levels in gimp, to make the difference between white and
>> almost-white (very light grey) visible. It can emphasize the contrast.
>> I saw the grid clearly then, but also saw the text
>> flag{youKnowWhosTheBoss} in the image itsself. (See for youself<http://imgur.com/IniFKKK>
>> )
>> I think that whould have been what you were supposed to find :)
>> They probably left some meta data lying around :)
>> Nice find!
>>
>>
>>
>> --
>> Met vriendelijke groet, Kind regards,
>> Maarten Hoogveld
>> Elevate BV
>>
>>
>> On Fri, Oct 4, 2013 at 2:53 PM, Minhaz A V <minhazav at gmail.com> wrote:
>>
>>> youKnowWhosTheBoss :)
>>>
>>>
>>> On Fri, Oct 4, 2013 at 5:21 PM, Shivam Dixit <shivamd001 at gmail.com>wrote:
>>>
>>>> Hello all
>>>>
>>>> Thank you for your suggestions. I was able to solve the question and it
>>>> was much *simpler* than I was expecting and it only required *reading
>>>> meta data* and finding the value of "*flag*". I was able to scan
>>>> through meta data using a tool provided on this website :
>>>>
>>>> http://imgops.com/
>>>>
>>>> The name of tool is *metapicz. *
>>>>
>>>>
>>>>
>>>> On Fri, Oct 4, 2013 at 3:26 PM, Minhaz A V <minhazav at gmail.com> wrote:
>>>>
>>>>> My bad just googled "stenography" and got to know Abbas and Maarten
>>>>> were suggesting the same..:D
>>>>>
>>>>>
>>>>> On Fri, Oct 4, 2013 at 3:21 PM, Maarten Hoogveld <
>>>>> m.hoogveld at elevate.nl> wrote:
>>>>>
>>>>>> Just a tip to prevent you spending hours looking at difficult to read
>>>>>> text, it's possible to solve in under 5 minutes.
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Met vriendelijke groet, Kind regards,
>>>>>> Maarten Hoogveld
>>>>>> Elevate BV
>>>>>>
>>>>>>
>>>>>> On Fri, Oct 4, 2013 at 11:47 AM, Minhaz A V <minhazav at gmail.com>wrote:
>>>>>>
>>>>>>> Shivam,
>>>>>>> out of curiosity I downloaded this image from doc and opened it in
>>>>>>> notepad++ and while going through its source I found something strange.
>>>>>>> It had a lot of English words which included those like *Typeenum,
>>>>>>> bottomOutsetlong, printOutputOptions*
>>>>>>> which are not available in normal images so just have a look if this
>>>>>>> can be of any help (otherwise I doubt this has something to do with
>>>>>>> Photoshop).
>>>>>>>
>>>>>>>
>>>>>>> Regards,
>>>>>>> Minhaz
>>>>>>>
>>>>>>>
>>>>>>> On Fri, Oct 4, 2013 at 2:40 PM, Maarten Hoogveld <
>>>>>>> m.hoogveld at elevate.nl> wrote:
>>>>>>>
>>>>>>>> Hi Shivam,
>>>>>>>>
>>>>>>>> You could dive into converting the image in a 2-D array of
>>>>>>>> intensity values and maybe even extracting the R, G and B channels
>>>>>>>> separately. Then analyze that data for patterns and slight deviations which
>>>>>>>> could indicate steganography of some sort.
>>>>>>>> However, I would first pick the low hanging fruit and just look at
>>>>>>>> the image. I see that the image is white with a very light grid. You could
>>>>>>>> try to load the image in gimp <http://www.gimp.org/> or paint.net<http://www.getpaint.net/>and see if you can see something more when you zoom in so you can see
>>>>>>>> individual pixels or adjust contrast, etc.
>>>>>>>> Good luck!
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> Met vriendelijke groet, Kind regards,
>>>>>>>> Maarten Hoogveld
>>>>>>>> Elevate BV
>>>>>>>>
>>>>>>>>
>>>>>>>> On Thu, Oct 3, 2013 at 10:08 PM, Shivam Dixit <shivamd001 at gmail.com
>>>>>>>> > wrote:
>>>>>>>>
>>>>>>>>> Hello all
>>>>>>>>>
>>>>>>>>> Not much discussions on this list nowdays, so I thought of sharing
>>>>>>>>> one of the questions which I came across recently in college CTF, and was
>>>>>>>>> unable to solve it.
>>>>>>>>>
>>>>>>>>> The question is the image below :
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> https://docs.google.com/file/d/0B4G8EjUmqNchUlg1cGI3UFl4SEE/edit?usp=sharing
>>>>>>>>>
>>>>>>>>> (Image is white, with some grids)
>>>>>>>>>
>>>>>>>>> I have to decrypt some information out of it. I am not able to
>>>>>>>>> think from where to start. I am *not* good at Image processing.
>>>>>>>>> Please give me some suggestions on how to start ?
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> *Cheers,*
>>>>>>>>> *Shivam*
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> OWASP_PHP_Security_Project mailing list
>>>>>>>>> OWASP_PHP_Security_Project at lists.owasp.org
>>>>>>>>> https://lists.owasp.org/mailman/listinfo/owasp_php_security_project
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> OWASP_PHP_Security_Project mailing list
>>>>>>>> OWASP_PHP_Security_Project at lists.owasp.org
>>>>>>>> https://lists.owasp.org/mailman/listinfo/owasp_php_security_project
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> *Cheers,*
>>>> *Shivam*
>>>>
>>>
>>>
>>
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>>
>>
>
>
> --
> Abhishek Das
>  IIT Roorkee
>
> _______________________________________________
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> OWASP_PHP_Security_Project at lists.owasp.org
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>
>


-- 
*Cheers,*
*Shivam*
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