Cross-service confused deputy prevention

The confused deputy problem is a security issue where an entity that does not have permission to perform an action can coerce a more-privileged entity to perform the action. In AWS, cross-service impersonation can result in the confused deputy problem. Cross-service impersonation can occur when one service (the calling service) calls another service (the called service). The calling service can be manipulated to use its permissions to act on another customer's resources in a way it should not otherwise have permission to access. To prevent this, AWS provides tools that help you protect your data for all services with service principals that have been given access to resources in your account.

We recommend using the aws:SourceArn and aws:SourceAccount global condition context keys in resource policies to limit the permissions that CloudWatch Omni gives another service to the resource. Use aws:SourceArn if you want only one resource to be associated with the cross-service access. Use aws:SourceAccount if you want to allow any resource in that account to be associated with the cross-service use.

CloudWatch Omni assumes IAM roles in your account to read your telemetry, both during setup and during evaluation. To prevent it from being used as a confused deputy, restrict the roles you create so that they can only be assumed on your behalf.

Setup and data-access roles

The space operator role, CloudWatchOmniOperatorRole, trusts the CloudWatch Omni service principal cloudwatch.amazonaws.com. CloudWatch Omni creates this role and applies the following trust policy when you set up a space. If you supply your own role instead, give it the same trust policy.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": { "Service": "cloudwatch.amazonaws.com" },
      "Action": ["sts:AssumeRole", "sts:TagSession", "sts:SetContext"]
    }
  ]
}

Because this role is assumed only by the CloudWatch Omni service principal to issue credentials for a space in your own account, its trust policy does not carry an aws:SourceAccount or aws:SourceArn condition. The confused-deputy protection for the role that another AWS service assumes is described in the next section.

Dataset integration execution role

Dataset integration reads your CloudWatch Logs data through a role that CloudWatch Logs assumes on your behalf. Because the calling service is CloudWatch Logs rather than CloudWatch Omni, this role's trust policy uses both aws:SourceAccount and aws:SourceArn to restrict the assumption to dataset integrations in your own account.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": { "Service": "logs.amazonaws.com" },
      "Action": "sts:AssumeRole",
      "Condition": {
        "StringEquals": { "aws:SourceAccount": "<YOUR_OWN_ACCOUNT_ID>" },
        "ArnLike": { "aws:SourceArn": "arn:aws:observabilityadmin:*:<YOUR_OWN_ACCOUNT_ID>:dataset-integration/*" }
      }
    }
  ]
}