: Confirms it is a 7-Zip archive. If the header was missing or corrupted, you would need to manually fix the magic bytes ( 37 7A BC AF 27 1C ). Step 2: Password Extraction (The "Base64" Trick)
: If you see a string ending in = , it's likely Base64.
: Right-click, extract, repeat. This is inefficient for 10+ layers. 11-20.7z
Based on standard Capture The Flag (CTF) methodologies for these types of archive challenges, here is a long-form write-up on how to solve it. File Name : 11-20.7z Category : Forensics / Misc
While there isn't a single famous global CTF challenge exclusively named , this file naming convention is a hallmark of forensics and steganography challenges where players must navigate deeply nested archives or "Russian Doll" files. : Confirms it is a 7-Zip archive
If "11-20" implies a range, this file likely contains 12.7z , which contains 13.7z , all the way to 20.7z or flag.txt .
: If the archive is password-protected, look at the filename. In some CTFs (like CodeBattle ), the password is the Base64-decoded version of the filename or a string found in the file metadata. : Right-click, extract, repeat
Flare-on 11 Challenge 5 Write-up — SSHD: | by Raviv Rachmiel