If my username and password to an EC2 instance was changed, how can I reset them?

Is the instance Windows? Also, are you managing your EC2 instance through Systems Manager? If so, you can use Systems Manager to reset passwords.

• Resetting passwords on managed nodes If you do not manage it through Systems Manager, here are the articles that provide steps outside Systems Manager.

For Windows see below (EC2 Rescue section):

• How can I reset the administrator password on an EC2 Windows instance?

If your instance is Linux and you are having an SSH issue, see below:

• I made changes to my EC2 instance's sshd_config file. Now I can't access my instance using SSH. How do I resolve this?

As always, before making changes, make sure to create a backup (EBS snapshot/AMI) to be able to roll back.

No, it's Linux or Ubuntu

Reset passwords and SSH keys on EC2 instances https://docs.aws.amazon.com/systems-manager/latest/userguide/automation-ec2reset.html

Thanks very much - This is exactly what we needed. Thanks for supplying the code too!