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Introduction # Hey everyone 👋 — In this Capture The Flag (CTF), we’re told that a file is broken and we need to figure out how we could repair it.
File # Looking at the file, we could see that it seems like it is a JFIF. The file itself can’t be opened.
Editing The Hex Value # That’s weird! — Referring to a Wikipedia article, the file SOI segment must start with FF D8. However, this starts with 5C 78. Let’s change that!
To edit the value, you could use hexedit:
sudo apt install hexedit # Install hexedit file # Edit the file. REPLACE FILE WITH YOUR FILENAME We would use hexedit to edit the file value. Simply add FF D8.
Boom! — You could write the file via ctrl+w to write and ctrl+x to quit.
Flag 🚩 # Boom! — We could now see the flag!
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This is a writeup about picoCTF, picoMini by CMU-Africa, Crack the Gate 1.
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Introduction # Hey everyone 👋 — In this Capture The Flag (CTF) task, we’re told to analyze a large log file with something hidden within.
Analyzing The File # The file seems like it’s encoded in base64. I would run a command to decode it.
cat logs.txt | base64 -d > logs_decoded.txt Decoded File # As we can see, the decoded log file seems like it’s actually a .PNG.
View # Looking at this .png file, we can see that a long string appears.
Extracting & Decoding Strings # Google offers great Optical Character Recognition (OCR) technology. It allows us to copy the string which is:
7069636F43544678666F72656E736963735F616E616C797369735F69735F616D617A696E675F61633165333538347D We can drop it in MagicChef using the Magic recipe. It would return the result from Hex.
Flag 🚩 # picoCTF{forensics_analysis_is_amazing_ac1e3584}
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This is a writeup for picoMini by CMU-Africa, Hidden In Plainsight.
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This is a write up for picoMini by CMU-Africa, Log Hunt.
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This is a picoCTF WriteUp for picoMini by CMU-Africa, Riddle Registry, that’s easy to understand and straightforward.