TryHackMe Compiled Challenge – Writeup

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In this short post, we are going to solve the Compiled challenge from TryHackMe by finding the flag inside the strings of a compiled program.

Table of Contents


Introduction – Compiled

The only instructions are the following:

Download the task file and get started.

And the description of the challenge is the following:

Strings can only help you so far.

Besides this information, the flag pattern is *********_****, so 9 characters, an underscore, and 4 characters.

The file we download has a .Compiled extension.

Let’s see what we can do with the strings…


Retrieving the flag from strings

strings in this context usually refer to the plaintext words we can extract from a compiled program.

The strings command is available in Linux, however because I was not on Linux when doing this, I searched for a strings extractor online and ended up on this website:

Retrieving the strings of a compiled file online on dcode.fr

I uploaded the .Compiled file (red box) and the extracted strings appear on the left column (green box).

Among the many results, we can find strings that seem to belong to a piece of code that tests a password against a value:

Excerpt of the strings results on dcode

Remember the flag pattern? It needs 9 characters, then an underscore, then 4 characters.

The first green box shows a suspicious text made of 9 letters, then %sCTF that we will conviniently ignore.

Two lines under it, we see a text that starts with an underscore and contains 4 letters.

Well, after trying, the flag is indeed the combination of those 2 values.

Flag:

DoYouEven_i***

The final letters are blurred to encourage you to do it yourself!


Final Thoughts – Compiled

This challenge was easy but it’s a good introduction to the strings command and how strings might be revealed and extracted from a compiled program.

We got a bit lucky on the flag…

Read more THM Writeups on pentestguides.com:


Disclaimer

This article is provided for educational purposes only.

All techniques demonstrated were performed in a controlled lab environment.

Do not attempt to reproduce these actions on systems you do not own or have explicit authorization to test.

I do not encourage or take responsibility for any illegal use of the information provided.

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