Linux CLI - Shells Bells | Advent of Cyber 2025 - Day 1

This guide contains the answer and steps necessary to get to them for the Linux CLI - Shells Bells room.

Table of contents

• Linux CLI

Linux CLI

1. Which CLI command would you use to list a directory?

   The answer to this question can be found in the text.

   Click for answer

   ls

2. Complete on machine: Identify the flag inside of the McSkidy's guide.

   After listing the directory, we can see a readme file. Lets read it using: cat README.txt.

   This tells us there is a hidden guide in the guides folder. We navigate into it and look for any files using:

   cd Guides
   ls -la
   

   Here we find the file '.guide.txt' which will hold the first flag. Opening it (cat .guide.txt) will automatically answer the question in Tryhackme.

   

   Click for answer

   THM{learning-linux-cli}

3. Which command helped you filter the logs for failed logins?

   The answer to this question can be found in the text.

   Click for answer

   grep

4. Complete on machine: Identify the flag inside the Eggstrike script.

   As stated in the text we look for failed login attempts in the 'auth' log.

   grep "Failed password" auth.log
   

   This gives us a few failed attempts for user 'socmas'. Next we will look into its home directory for any suspicious files.

   find /home/socmas/ -name *eggs*
   cat /home/socmas/2025/eggstrike.sh
   

   Here we see a possibly malicious script file. Opening it reveals the next flag.

   

   Click for answer

   THM{sir-carrotbane-attacks}

5. Which command would you run to switch to the root user?

   The answer to this question can be found in the text.

   Click for answer

   sudo su

6. Finally, what flag did Sir Carrotbane leave in the root bash history?

   To view the bash history of the roort user, we must first switch to the root user using sudo su. Now we can use history to view the used bash commands.

   

   Indeed we find the flag left behind for us.

   Click for answer

   THM{until-we-meet-again}

7. For those who consider themself intermediate and want another challenge, check McSkidy's hidden note in/home/mcskidy/Documents/to get access to the key forSide Quest 1!

   Navigating to '/home/mcskidy/Documents/' we find a file called 'read-me-please.txt'. This files contains some information and several clues needed for us to find the key for the first sidequest of 2025. This will be further investigated in Advent of Cyber '25 Side Quest

   Click for answer