Chaining STS assume role across 3 aws accounts

Question

There is an AWS account A, which has a resource X managed by policy Pax. It adds the second AWS account B to a role which attaches the policy Pax, let's call this role Rax. Now within the AWS account B, I create another policy for assuming role Rax, let's call it Pbrax and added it to a role RPbrax where the Principal is an AWS account C.

When I try to access the resource X via the account C, I get access denied. I cannot touch anything in AWS account A, but in B and C.

Answer 1

Role permissions are not cumulative.

This means the history of the role chaining doesn't help you - the principal in account C needs to have its own access to the resources in account X if needs to access them.