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

Maarten Hoogveld m.hoogveld at elevate.nl
Fri Oct 4 13:43:05 UTC 2013


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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