By default your administrative username is admin. The majority of the attackers would expect the username to be admin. Changing it will protect you against many attacks.
To do this, you should:
Step 1. Log in to the Joomla administrative area and click on the User Manager menu.
Step 2. Click on your administrative user in order to edit it. You can either check the box next to the user and click the "Edit" button or directly click on the user's full name.
Step 3. In the next page you should edit the Username field. Change it to something different than "admin" and click on the "Save" button.
Alternatively, you can do this by modifying the database of your Joomla website:
Step 2. Select the jos_users table from the left column and click on the Browse button to edit the rows in it.
Step 3. Locate the line for the "admin" username and click on the pen icon next to it to edit it.
Step 4. Change the value of the "username" field to something different than "admin". Using lower and upper case characters as well as numbers is highly recommended. Step 5. Once you change your administrative username, press the Go button at the bottom right part of the page.
Now you can login to the administrative area of your Joomla application with the new username.
