TryHackMe Writeup: Recovery CTF

TryHackMe Writeup: Recovery CTF

In this article, I will be demonstrating my approach to completing the Recovery Capture The Flag (CTF), a free room available on the TryHackMe platform created by deltatemporal.

In this article, I will be demonstrating my approach to completing the Recovery Capture The Flag (CTF), a free room available on the TryHackMe platform created by _deltatemporal. _I have provided a link to the TryHackMe platform in the references below for anyone interested in trying out this CTF.


I like to add a brief disclaimer before a writeup to encourage people to attempt the room before reading this article, since there will obviously be spoilers in this writeup. I believe you will enjoy the CTF more if you attempt it yourself first and then come back to this writeup if you get stuck or need a hint!

This is not your conventional CTF and so I found myself finding some flags before others. This will be reflected in my writeup , so just search for the flag you are stuck on if you don’t want any spoilers for other flags. Without any further delay, lets dive in!

CTF Background — Help Alex!

The following background is provided for the CTF and I have highlighted some important pieces of information in the description provided. Always read the challenge description carefully!!! (foreshadowing 😅)

Hi, it’s me, your friend Alex.

I’m not going to beat around the bush here; I need your help. As you know I work at a company called Recoverysoft. I work on the website side of things, and I setup a Ubuntu web server to run it. Yesterday one of my work colleagues sent me the following email:

_Hi Alex,_

_A recent security vulnerability has been discovered that affects the web server. Could you please run this binary on the server to implement the fix?_


_- Teo_

Attached was a _**_linux binary_ called _fixutil**. As instructed, I ran the binary, and all was good. But this morning, I tried to log into the server via SSH and I received this message:




It turns out that Teo got his mail account hacked, and fixutil was a targeted malware binary specifically built to destroy my webserver!

when I opened the website in my browser I get some crazy nonsense. The _**_webserver files had been encrypted**! Before you ask, I don’t have any other backups of the webserver (I know, I know, horrible practice, etc…), I don’t want to tell my boss, he’ll fire me for sure.

Please access the web server and _**_repair all the damage_ caused by fixutil. You can find the binary in my__ home directory_**. Here are my ssh credentials:

_Username: alex_

_Password: madeline_

I have setup a control panel to track your progress on port 1337._ Access it via your web browser. As you repair the damage, you can refresh the page to receive those “flags” I know you love hoarding._

tryhackme malware-analysis cybersecurity reverse-engineering capture-the-flag data analysis

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