Cybergon CTF

Achieved Rank 3 🥉

Name	Category	Solved?
Invisible	Stegano	✅
Truesight	Stegano	✅
What’s behind the wall ?	Stegano	✅
Triple Quiz	Misc	✅

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Stegano

Invisible [50 Pts]

Description

Sometimes it’s a relief to be invisible. CYBERGON_CTF2024

Author - iamkfromburma

Solution

Given an image file challenge1.jpg, let’s try find something using Aperisolve.

There’s something interesting in the Red section.

We can see that there’s getyourflag on the bottom left of the picture.

let’s try using steghide extract -sf challenge1.jpg and getyourflag as the passphrase

and we got a flag.txt file

Flag

CYBERGON_CTF2024{n07h1ng_5t4ys_h1dd3n}

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Truesight [50 Pts]

Description

If you are waiting for a sign, this is it. CYBERGON_CTF2024

Author - iamkfromburma

Solution

We are given a png file but is corrupted.

let’s try checking it using a hexeditor

As expected, we’re missing the first 8 bytes of the png header. let’s try adding it

Save it and we can now view the png file

Flag

CYBERGON_CTF2024{y0u_g07_7h3_r!gh7_s!gn5}

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What’s behind the wall ? [50 Pts]

Description

Find the secret behind the wall ? CYBERGON_CTF2024

Author - iamkfromburma

Solution

We are given an image challenge4.jpg and a JS.txt file from the challenge.

Let’s try check the image metadata first using exiftool

ExifTool Version Number         : 13.00
File Name                       : challenge4.jpg
Directory                       : .
File Size                       : 180 kB
File Modification Date/Time     : 2024:09:28 01:28:53+07:00
File Access Date/Time           : 2024:11:30 18:33:47+07:00
File Inode Change Date/Time     : 2024:11:30 18:33:49+07:00
File Permissions                : -rwxrwxrwx
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
JFIF Version                    : 1.01
X Resolution                    : 72
Y Resolution                    : 72
Exif Byte Order                 : Big-endian (Motorola, MM)
Resolution Unit                 : inches
Y Cb Cr Positioning             : Centered
Exif Version                    : 0232
Components Configuration        : Y, Cb, Cr, -
User Comment                    : winteriscoming
Flashpix Version                : 0100
Image Width                     : 1920
Image Height                    : 1080
Encoding Process                : Progressive DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:0 (2 2)
Image Size                      : 1920x1080
Megapixels                      : 2.1

I saw winteriscoming on user comment, maybe we can use it for something related to txt files. since there is nothing else we can do by using jpg files. let’s try to find some steganography tools related to Text.

After some research, I found a tool called Snow and it’s for a text-based steganography. let’s try using it

Command: ./SNOW.EXE -C -p "winteriscoming" JS.txt

Output: 3X1f_w1th_5n0w5

Flag

CYBERGON_CTF2024{3X1f_w1th_5n0w5}

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Misc

Triple Quiz [50 Pts]

Description

You’ll recognize it when you see it, it’s something you’ve already done before.

CYBERGON_CTF2024 Author - iamkfromburma

Solution

We are given a password protected rar file. we can try to crack it using john the ripper.

rar2john Triple_Quiz.rar > cek.hash -> Extracting the hash of the rar file

john --wordlist=/usr/share/wordlists/rockyou.txt cek.hash -> cracking using rockyou

and we get the password ICEMAN

After extracting the rar file, we got a .wav file. By hearing it, I suspect that this audio is a morse code.

Let’s try decode it using Morse Code Decoder and we got this 6 666 777 7777 33 9 444 8 44 8 66 444 66 33

let’s try using cipher identifier in dcode

Flag

CYBERGON_CTF2024{MORSEWITHTNINE}