Enforce Http Token Imds

aws_instance should activate session tokens for Instance Metadata Service.

IMDS v2 (Instance Metadata Service) introduced session authentication tokens which improve security when talking to IMDS.

By default aws_instance resource sets IMDS session auth tokens to be optional.

To fully protect IMDS you need to enable session tokens by using metadata_options block and its http_tokens variable set to required.

Impact

Recommended Actions

Follow the appropriate remediation steps below to resolve the issue.

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resource "aws_instance" "good_example" {
  ami           = "ami-005e54dee72cc1d00"
  instance_type = "t2.micro"
  metadata_options {
    http_tokens = "required"
  }
}

Links

• https://aws.amazon.com/blogs/security/defense-in-depth-open-firewalls-reverse-proxies-ssrf-vulnerabilities-ec2-instance-metadata-service