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Nature Symphony - CTF Writeup
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Nature Symphony - CTF Writeup

·197 words·1 min·
Writeups Forensics
Deadnaut
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Deadnaut
Documenting cybersecurity challenges, CTF writeups, and penetration testing insights from the digital frontier.
Table of Contents

Challenge Name: Nature Symphony
Category: Forensics
CTF: MOJO-JOJO
Description: While exploring an abandoned research facility, you discovered two audio recordings labeled rain.wav and fire.wav.The recordings seem ordinary at first - just sounds of nature. But something feels off…

Overview
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This challenge involves decoding Morse code from two audio files: fire.wav and rain.wav. Both files contain Morse audio signals that are not initially clear, but can be analyzed using audio editing software like Audacity.

Audio Analysis
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When the audio files are opened in Audacity and viewed in the spectrogram mode, the Morse characters become visible. The following Morse code sequences were extracted:

Extracted Morse Code
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  • From fire.wav:

    -- .--- -...- --- --- .---- .-.. ...- ..--.- ..- .. ..--.- . . ...-- .
Alt text

  • From rain.wav:

    --- --- .--- .--- -.--. ..--.- ---- ...-- .- -.. ----- .... .... .... .... -.--.-
Alt text

Morse Code Conversion
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Converting the extracted Morse code to characters yields:

  • From fire.wav:
    MJ=OO1LV_UI_EE3E
Alt text
  • From rain.wav:
    OOJJ(_3AD0HHHH)
Alt text

Flag Format
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The known flag format begins with:

MOJO-JOJO{

To construct the final flag, we alternate each letter from the decoded messages:

  • Alternating Letters:
    • MOJO=JOJO(1_L0V3_AUDI0_HEHEH3HE)
Alt text

Final Flag
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This results in the final flag:

MOJO-JOJO{1_L0V3_AUDI0_HEHEH3HE}

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