A daily CTF challenge with a fun new puzzle every day
We publish one simple, beginner-friendly or educational CTF challenge every day! Selected problems from external CTFs are released occasionally.
Solve within 24 hours of release to appear on the leaderboard.
Discussion with friends or AI is welcome (account sharing is prohibited).
Sharing solutions is allowed only after 24 hours have passed since release (mirrored past challenges are excluded).
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Try the first challenge
Is this your first CTF? Let's begin by tackling the first challenge released on Daily AlpacaHack.
Topic: Out-of-Bounds Write
If the return address gets overwritten by accident, you could even spawn a shell... but this program is totally safe, right?
main.c とそれをコンパイルしたバイナリ chal が与えられています。pos, val の入力を受け付けます。win 関数を実行してシェルを起動することです。pos, val を送信すると win 関数が呼べるので、そのような値を見つけてください。nc コマンドで接続します。flag.txt を読んで、フラグを取得してください。