This document describes the complete procedure to create a Linux user, grant sudo access, enable SSH password authentication, and verify access on an Ubuntu server (AWS EC2 compatible).

Login to the server where the user needs to be created.

ssh ubuntu@<server-ip>

Create the user if it does not already exist.

sudo adduser shivam

Follow the prompts to set the password and user details.

Add the user to the sudo group to allow administrative privileges.

sudo usermod -aG sudo shivam

Verify the group assignment:

groups shivam

Edit the main SSH configuration file.

sudo vi /etc/ssh/sshd_config

Ensure the following lines exist and are set exactly as shown:

PasswordAuthentication yes
UsePAM yes
KbdInteractiveAuthentication no

If the lines are commented (#), uncomment them.

Save and exit the file.

Cloud-init can override SSH settings on AWS EC2 instances.

Edit the cloud-init SSH configuration file:

sudo vi /etc/ssh/sshd_config.d/50-cloud-init.conf

Ensure the following line exists:

PasswordAuthentication yes

Save and exit the file.

Restart the SSH service to apply changes.

sudo systemctl restart ssh

Verify SSH service status:

sudo systemctl status ssh

Ensure the service is running without errors.

Set correct ownership and permissions for the user home directory.

sudo chown -R shivam:shivam /home/shivam
sudo chmod 700 /home/shivam

Login using the newly created user via private IP (VPN required).

ssh shivam@10.0.2.192

Enter the password when prompted.

If the user already exists and requires sudo access:

sudo usermod -aG sudo shivam

Logout and login again for group changes to take effect.