The PNG file was striped and hidden in the trailing bytes of the 7z archives, just before the footer.

The first file contained the start of the PNG, while the last file ( part2_375.7z ) contained the .

The challenge provided a set of 376 individual 7zip archives (e.g., part2_0.7z through part2_375.7z ). Inside these archives were multiple "junk" files (e.g., junk_0.bin ), which initially appeared to be the primary data for extraction. Analysis & Solution

The file Parade_Buster-Final.7z was the concluding challenge in the series from TastelessCTF 2020 . This write-up details the process of identifying a hidden PNG file embedded across hundreds of separate archives. Challenge Overview

: To solve this, a script was used to loop through all 376 files, extract a specific block of bytes (typically 0x11 bytes) from each, and concatenate them. Final Result

The offset for the hidden PNG data could be calculated by comparing the reported "Packed Size" from the 7z -slt l command with the actual file structure.

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Parade_buster-final.7z

The PNG file was striped and hidden in the trailing bytes of the 7z archives, just before the footer.

The first file contained the start of the PNG, while the last file ( part2_375.7z ) contained the . Parade_Buster-Final.7z

The challenge provided a set of 376 individual 7zip archives (e.g., part2_0.7z through part2_375.7z ). Inside these archives were multiple "junk" files (e.g., junk_0.bin ), which initially appeared to be the primary data for extraction. Analysis & Solution The PNG file was striped and hidden in

The file Parade_Buster-Final.7z was the concluding challenge in the series from TastelessCTF 2020 . This write-up details the process of identifying a hidden PNG file embedded across hundreds of separate archives. Challenge Overview Inside these archives were multiple "junk" files (e

: To solve this, a script was used to loop through all 376 files, extract a specific block of bytes (typically 0x11 bytes) from each, and concatenate them. Final Result

The offset for the hidden PNG data could be calculated by comparing the reported "Packed Size" from the 7z -slt l command with the actual file structure.