In practice, it's pretty normal to use OIDC to authenticate Github Actions to AWS:
https://docs.github.com/en/actions/deployment/security-harde...
They should update the main readme to include this under Features, and also call it out in the demo files.
I am a co-founder of Terrateam[0] which is a Terraform CI/CD as well. At the end of the day, you need to execute something to do these operations and having this component open source is important for auditing purposes. For Terrateam, we lean heavily into GitHub Actions so GitHub is at least managing any secrets and runs. One challenge is users could pin the Action that we publish to a specific version, but we also update it regularly and communicating to customers to update it is a challenge.
https://docs.digger.dev/cloud-providers/authenticating-with-...
Still need a more permissive role to manage the cluster in other ways but you can isolate that and limit access to its repo.
This does require something that should essentially be embedded in your environment or account vending machine, otherwise it becomes very cumbersome to maintain.
Digger makes it sound like it might address this:
> Digger runs terraform natively in your CI. This is: Secure, because cloud access secrets aren't shared with a third-party
From the Github+AWS demo:
> 4. Add environment variables into your Github Action Secrets (cloud keys are a requirement since digger needs to connect to your account for coordinating locks) AWS_ACCESS_KEY_ID & AWS_SECRET_ACCESS_KEY
It sure looks like AWS admin credentials are shared with Github, and also available to anything else in the diggerhq/digger action.