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Tag: Flag Checker

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Flag Checker

Flag checkers are a common type of challenge in the Reverse Engineering category.

An executable or script called a flag checker takes the player's input and outputs whether that input matches the flag.

These challenges may also be called "crackmes" in a broader sense. (automatically translated from Japanese)

minaminao
·Updated May 3, 2026
Flag Checker Challenges

read-a-binary

Daily AlpacaHackTopic: ELFReleased: Feb 3, 2026

253 solves
Rev

by

tan90909090

tan90909090

🦙 < Let's try reading what the ELF binary does!

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 file is the ELF binary read-a-binary.
  • The goal is to find an input (the flag) that makes the binary print Correct! by analyzing the binary.
  • There are a variety of tools available that can analyze ELF binaries.
  • Some tools can show a higher level of representations than others.
read-a-binary

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