[Basic Stegano] Cum sa bem bere 1337 cu Hertz

[Flubber]

In incheierea evenimentului DefCamp Bucuresti 2013 pentru after party s-a pus un basic stegano la dispozitia tuturor, iar cine oferea raspunsul ii se dadea un bax de bere.

Poza era (click pe 404 image sa se deschida in tab nou):

$ hexdump -C stegano.bmp | tail -10

00002b20  0c 00 00 00 73 6f 6c 75  74 69 6f 6e 2e 74 78 74  |....solution.txt|
00002b30  f3 54 28 4f cc 2b 51 48  54 c8 49 4d 2d 51 48 29  |.T(O.+QHT.IM-QH)|
00002b40  ca cc cb 56 48 2b ca cf  55 f0 48 2d 2a a9 d2 e3  |...VH+..U.H-*...|
00002b50  e5 02 00 50 4b 01 02 14  00 14 00 02 00 08 00 26  |...PK..........&|
00002b60  7e 7e 43 da 67 72 72 23  00 00 00 21 00 00 00 0c  |~~C.grr#...!....|
00002b70  00 00 00 00 00 00 00 01  00 20 00 00 00 00 00 00  |......... ......|
00002b80  00 73 6f 6c 75 74 69 6f  6e 2e 74 78 74 50 4b 05  |.solution.txtPK.|
00002b90  06 00 00 00 00 01 00 01  00 3a 00 00 00 4d 00 00  |.........:...M..|
00002ba0  00 00 00                                          |...|
00002ba3

Iese in evidenta solution.txt

O varianta sa extragem acest fisier:

Din:

1. $ hexdump -C stegano.bmp | head -1

   00000000  [B][COLOR=red]42 4d 06 2b[/COLOR][/B] 00 00 00 00  00 00 36 04 00 00 28 00  [B][COLOR=red]BM.+[/COLOR][/B]......6...(.

   
   

2. In

   00000000  [B][COLOR=green]2e 5a 49 50[/COLOR][/B] 00 00 00 00  00 00 36 04 00 00 28 00  [B][COLOR=green].ZIP[/COLOR][/B]......6...(. 

   
   

Ne ramane sa dezarhivam si sa aflam raspunsul:

[B][I]$ mv stegano.bmp stegano.zip[/I][/B]


[B][I]$ unzip stegano.zip[/I][/B]
Archive:  stegano.zip
warning [stegano.zip]:  11014 extra bytes at beginning or within zipfile
  (attempting to process anyway)
  inflating: solution.txt            

[B][I]$ cat solution.txt [/I][/B]
I want a leet drink from Hertz

Edited December 1, 2013 by Flubber