Ensure AMIs Are Private

AWS remediation

Console

1. Open the AMI in EC2.
2. Select Actions -> Edit AMI permissions.
3. Remove public launch permission (All).
4. Keep sharing only with specific AWS accounts if needed.

AWS CLI

aws ec2 modify-image-attribute \
  --image-id <ami-id> \
  --launch-permission "Remove=[{Group=all}]"

aws ec2 modify-image-attribute \
  --image-id <ami-id> \
  --launch-permission "Add=[{UserId=<account-id>}]"

References

• https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/sharingamis-explicit.html
• https://docs.aws.amazon.com/cli/latest/reference/ec2/modify-image-attribute.html

Multiple Remediation Paths

AWS

SERVICE-WIDE (RECOMMENDED when many resources are affected): Deploy centralized guardrails and remediation using AWS Config Conformance Packs and (if applicable) AWS Organizations SCPs.

aws configservice put-organization-conformance-pack --organization-conformance-pack-name <pack-name> --template-s3-uri s3://<bucket>/<template>.yaml

ASSET-LEVEL: Apply the resource-specific remediation steps above to only the affected assets.

PREVENTIVE: Add CI/CD policy checks (CloudFormation/Terraform validation) before deployment to prevent recurrence.

References for Service-Wide Patterns

• AWS Config Conformance Packs: https://docs.aws.amazon.com/config/latest/developerguide/conformance-packs.html
• AWS Organizations SCP examples: https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_policies_scps_examples.html

Operational Rollout Workflow

Use this sequence to reduce risk and avoid repeated drift.

1. Contain at Service-Wide Scope First (Recommended)

• AWS: deploy/adjust organization conformance packs and policy guardrails.

aws configservice put-organization-conformance-pack --organization-conformance-pack-name <pack-name> --template-s3-uri s3://<bucket>/<template>.yaml

2. Remediate Existing Affected Assets

• Execute the control-specific Console/CLI steps documented above for each flagged resource.
• Prioritize internet-exposed and production assets first.

3. Validate and Prevent Recurrence

• Re-scan after each remediation batch.
• Track exceptions with owner and expiry date.
• Add preventive checks in IaC/CI pipelines.