Issue with cross account access with Secrets Manager

Question

Hi, I have a secret in account 111111111111 and I'm trying to access it from account 222222222222.

To do this I followed this tutorial https://docs.aws.amazon.com/secretsmanager/latest/userguide/auth-and-access_examples_cross.html

I have this policy attached to a role called `my-super-role`

``` 
{ 
    "Version": "2012-10-17", 
    "Statement": [ 
        { 
            "Effect": "Allow", 
            "Action": [ "secretsmanager:GetSecretValue" ], 
            "Resource": [ "arn:aws:secretsmanager:sa-east-1:111111111:secret:mysecret" ] 
        }, 
        { 
            "Effect": "Allow", 
            "Action": [ "kms:Decrypt" ], 
            "Resource": [ "arn:aws:kms:sa-east-1:111111111:key/random-uuid" ] 
        } 
    ] 
} 
```

and this resource policy in the secret `mysecret`

``` 
{ 
    "Version": "2012-10-17",
    "Statement": [ 
        { 
            "Effect" : "Allow", 
            "Principal" : { 
                "AWS" : "arn:aws:iam::222222222:role/my-super-role" 
            }, 
            "Action" : "secretsmanager:GetSecretValue", 
            "Resource" : "*" 
        } 
    ] 
} 
```

and I get the error

```
 User: arn:aws:sts::222222222:assumed-role/my-super-role/i-xxxxxxxxxx is not authorized to perform: secretsmanager:GetSecretValue on resource: arn:aws:secretsmanager:sa-east-1:111111111:secret:mysecret because no resource-based policy allows the secretsmanager:GetSecretValue action 
```
I've also specified the ARN of the secret in the resource policy of itself and that didn't change anything

Answer

I don’t see a resource policy for the KMS key in account 1111111111 to allow the role from account 2222222222 to decrypt. Step 2 from your link.

Could this be the reason?

Answer

Hi Gary, thanks for the quick answer.

I have this policy in my KMS key

```
{
    "Version": "2012-10-17",
    "Id": "some-id",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "AWS": "arn:aws:iam::arn:aws:iam::222222222:role/my-super-role"
            },
            "Action": [
                "kms:Decrypt",
                "kms:DescribeKey"
            ],
            "Resource": "*"
        }
    ]
}
```
along many others statements that come by default when you create a new key. could it be that the problem?

Answer

Try updating the resource policy’s in account 111111111 to use this principle arn:aws:sts::222222222:assumed-role/my-super-role/I-xxxxxxxxxxx

On KMS and Secret policy

Instead of the iam principal

Issue with cross account access with Secrets Manager

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