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Leaked Flag Checker

Daily AlpacaHackTopic: C, Flag CheckerReleased: Dec 4, 2025

611 solves
Rev
Easy🌱

by

minaminao

minaminao

flag checker everyone loves

Beginner Hint
  • This challenge is in the Rev (Reverse Engineering) category.
  • Flag checkers are a common theme in Rev problems.
  • A flag checker executable or script accepts player input and tells you whether it matches the flag.
  • The provided files are the C source challenge.c and its Ubuntu 24.04 binary build challenge.
  • In challenge.c, the flag-related string xor_flag has been edited out and hidden.
  • The goal is to use challenge.c as a reference and find an input (the flag) that makes the challenge binary print Correct.
  • Typically Rev problems don't include source code. You usually analyze only the binary. This one can also be solved without the source.
leaked-flag-checker.tar.gz

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