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Missing Identity

Question

Turns out, some of the files back from Master Challenge 1 were corrupted. Restore this one file and find the flag. Update 16:26 EST 1 Apr If you feel that you are close, make a private piazza post with what you have, and an admin will help out. The flag starts with the character z.

HINTS

What file is this? What do you expect to find in the file structure? All characters in the file are lower case or numberical. There will not be any zeros.

Solution

So now lets to this master challenge of Level two. This challenge will open your door to Level 3. This challenge was easy not that must hard. Just be focused and you will be be fine.

  1. So we downloaded the file

  2. Lets check which type of file it is:-

    $ file file
file: data

  3. Now lets do some enumeration.

    $strings file | more
 XXXXXX
 flag.png
 IHDR
 IDATx
 -6.V
 e~}e
 ->x>)
 hJwv0=
 q0yU
 ZY&Q
 `>=*U,
 jLNf
 jv@D
 v?kV
 {&p%
 aO~|<
 gs3'
 |~XS
 t_H%
 'Twl]Z
 -bD@
 e+*'
 }svZ
 300Jp
 0.NL
 PZIT
 _|k*
 @avT
 <r	(A(
 :Y,/
 JgZk
 IOo~
 F!Q(D
 p5uw
 tw>*
 /2330
 ndI+^_7Q
 &ghU
 --More--

    So just look at the starting XXXXXX it means invalid header is given and we can see the flag.png also lets copy this file file in .zip format.

    $cp file spirit.zip
$unzip spirit.zip 
 Archive:  spirit.zip
 file #1:  bad zipfile offset (local header sig):  0
 inflating: nottheflag1.png         
 inflating: nottheflag2.png         
 inflating: nottheflag3.png         
 inflating: nottheflag4.png         
 inflating: nottheflag5.png         
 inflating: nottheflag6.png         
 inflating: nottheflag7.png

  4. So as you can see bad zipfile offset . So now lets open HexEditior and give the correct header offset. Read This

    we need to change

    58 58 58 58 58 58 00 00 08 00 22 44 7F 4A B4 8B E4 67 2B 90 00 00 1C 90 00 00 08 00 00 00 66 6C 61 67 2E 70 6E 67 00 66 40 99 BF 89 50 4E 47 0D 0A 1A 0A 00 00 00 0D 49 48 44 52 00 00 02 81 00 00 00 3C 08 02 00 00 00 96 FA F7 6D 00 00 8F E3 49 44 41 54 78 9C EC FD 59 AF 6C D9 96 1E 86 8D 31 9B D5 45 1F BB 3F 6D B6 37 33 6F DE AE EA 96 CC 2A 56 D9 34 8B B2 20 1B 86 4C 91 80 21 D8 16 0C 43 06 FC E6 27 FD 0C C2 80 FC E2 27 FA C1 10 6C 58 76 D1 86 21 C0 B2 45 53 02 2D 36 2E 56 CB BA 75 9B 6C 4F BB FB 1D ED EA E6 9C 63 CE E1 87 15 11 3B 76 7B F6 3E 37 F3 B2 AA C8 C1 2C E2 DC 73 22 56 AC 66 AE 39 BA EF FB 06 9A F9 18 6E B6 DF FF 87 3F B1 73 57 BD E4 FF DE FF FA D7 6F F9 D8 BD EC FF F3 BF FB 93 E0 C2 CE 7F 2B FB CE 0F DF F9 67 BF F7 53 00 08 39 30 01 87 EB 3F 8F 02 9E FE AD C1 F1 17 53 00 A8 0F 7D 30 02 00 20 F0 EA 03 42 81 DE 86 CE 66 0C 00 BF F6 DF FD F4 96 9F 36 C6 FE D3 FF E3 4F A8 04 F0 97 FE 85 45 0A 18 A3 CE C0 1B 70 67 E7 FF 20 63 F1 BB FF AB 1F BD C5 65 FE 1B BB 6A BF F8 B3 2F 01 E0 A3 EF BF FF 6D 1C FC F7 FF E1 4F 3E F8 D1 C3 E1 E6 E0 8E 9F FF 83 FF FA 27 E3 9F DA CE BB B2 7C C1 DE DC B0 F8 EE 60 28 20 DA 82 EE 93 E4 DD 4F 1E F5 FA DD B7 3E CE BF B1 5F 8D FD D7 FF A7 3F F2 33 8E 06 C2 E5 C1 57 28 53 06 27 E3 5D 26 CB A1 86 BF F9 1F 7E 63 1B DD B7 6A AF 9E EF 3F 7A FA 00 00 FE C5 3F FC 33 57 FB BF FE 3F FC D1 9F FC 37 3F FD D1 EF 7C F7 97 39 E6 D1 FE C9 4F FF AB 97 00 E0 4B E0 EA E2 BF 09 44 C9 00 C0 1E 21 30 08 5C DF 81 65 0F 36 BE 93 FD F0 B7 3E FE 65 7E 7D 65 FF E5 FF F6 8F AE FE A5 EA 01 48 7E FF 77
---more---

    we need to change 58 58 58 58 58 58 to 50 4B 03 04 00 00

    and save the file as spirit-new.zip

  5. Just unzip

    $unzip spirit-new.zip
Archive:  spirit-new.zip
inflating: flag.png                
inflating: nottheflag1.png         
inflating: nottheflag2.png         
inflating: nottheflag3.png         
inflating: nottheflag4.png         
inflating: nottheflag5.png         
inflating: nottheflag6.png         
inflating: nottheflag7.png

    Just open the flag.png and you got the flag.  

    Thanks :)

    @spiritedwolf