I've been trying to get cross account ec2 role authorisation working for a while now but seem to be hitting a bit of a dead end. We currently have cross account user authentication which is working well, however expanding that to cross account ec2 role access doesn't seem possible as far as I can tell?

I came across the following Cross Account Article, which basically undertook the same steps I had with similar results. Has a workaround for this come to fruition yet, or is it still required to use the Use-STSRole powershell/aws assume-role trick?


For our use case it required amending the bucket policy to trust the account principal, rather than a specific role within it, and then controlling who was allowed that access in the usual IAM role manner.

For reference, http://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_create_policy-examples.html#example-delegate-xaccount-S3 and sample bucket policy below.

    "Version": "2012-10-17",
    "Statement": [
            "Sid": "Allow Development Read-only Access",
            "Effect": "Allow",
            "Principal": {
                "AWS": "012345678910"
            "Action": [
            "Resource": [
  • I'm having this same problem, but I think the problem is related to the KMS key permissions. – szeitlin Jul 30 '18 at 21:02

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