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Rémi Lavedrine
Rémi Lavedrine

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Bandit CTF - 1 to 5 Challenges WriteUp

Knowing where to start when I'm interested in offensive computer security can be tricky.
Should you read a book (s)? Read as many articles as possible? Make a formation ? Watch videos on Youtube?

There are many possibilities.

But beyond all this, it is certain that at one time or another nothing will replace practice.

This is when the CTF (Capture The Flag) becomes your best ally to put into practice everything you have learned.
OverTheWire CTFs are intended for beginners. But it is in this that they are extremely rewarding because they allow Security Engineers but also Software Engineers to understand the challenges of IT security.
Indeed, the first challenges are oriented on the exploitation of vulnerabilities via simple bash commands.

I suggest you do these challenges and explain how to solve the challenges of this CTF. The idea is more to understand how a command works and how to use all its possibilities to carry out a vulnerability exploitation on the system.

We start with the first 5 challenges:

Video with French Audio & English Subtitles

If you want to read the writeup without the voice over, here are all the writeups (for the 5 first challenges).

Bandit Level 0 -> 1
ssh -p 2220
Use bandit0 as the password

Read the readme file

more readme
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Flag : boJ9jbbUNNfktd78OOpsqOltutMc3MY1

Bandit Level 1 -> 2
ssh -p 2220
Use the boJ9jbbUNNfktd78OOpsqOltutMc3MY1 flag as the password.

Create a directory in /tmp with

mktemp -d /tmp/ploptipXXXX
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Return : /tmp/ploptipfmHI

Move the - file to that directory while modifying the name to a more "normal" one.

mv - /tmp/ploptipfmHI/flag.txt
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Bandit Level 2 -> 3
ssh -p 2220
Use the CV1DtqXWVFXTvM2F0k09SHz0YwRINYA9 flag as the password.

Read the spaces in this filename file

more spaces\ in\ this\ filename
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Flag : UmHadQclWmgdLOKQ3YNgjWxGoRMb5luK

Bandit Level 3 -> 4
ssh -p 2220
Use the UmHadQclWmgdLOKQ3YNgjWxGoRMb5luK flag as the password.

The flag is in a hidden file.
Use the ls -a command to display all files.

.hidden file is revealed.

ls -la
more .hidden
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Flag : pIwrPrtPN36QITSp3EQaw936yaFoFgAB

Bandit Level 4 -> 5
ssh -p 2220
Use the pIwrPrtPN36QITSp3EQaw936yaFoFgAB flag as the password.

We are using a recursive cat on all the files that are in the folder.hidden/

cat ./-file00 etc...
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You can do that super quickly through cat ./-file0*

Flag : koReBOKuIDDepwhWk7jZC0RTdopnAYKh

If you have any question, feel free to ask and I'll do my best to answer it and help you grow.

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