How to login to EC2 Linux instance if sudo password is not known?

Question

I am trying to login to my EC2 Linux instance, but someone has changed the sudo password. So I could not install or uninstall any application.

Answer 1

If your EC2 instance is EBS-backed, and you can shut it down, you can do the following:

1. Stop the old instance.
2. Detach the root volume from the old instance.
3. Start a new instance.
4. Attach the old volume to the new instance
5. edit the sudoers file on the old volume you just mounted, making your user a password-less sudoer.
6. Stop the new instance.
7. Detach the old volume from the new instance.
8. Re-attach the old volume to the old instance and start it up.

You should now have password-less sudo permissions.