Running Out of Time

"Binary Exploitation"

A mysterious program asks for a specific number, but the correct value changes every time you run it. Can you figure out how the number is generated and retrieve the hidden flag?

Analyze the binary, reverse-engineer the logic, and find a way to predict the correct input to trigger the win condition.

I couldn't really upload the file because it's a .exe LOL

Given a binary for Windows called "Running_Out_Of_Time.exe", we decided to decompile with Ghidra. Because there was no nc, it means that we definitely can just do static analysis.

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In the main function it looked like a simple RNG prediction challenge, but it looked like it just goes to a function called p3xr9q_t1zz, so we looked on it.

Screenshot 2025-02-27 165400

So we were lazy to type all of the characters to decode the flag so we just opened DeepSeek:

Screenshot 2025-02-27 165352

Flag: ACECTF{71m3_570pp3d}