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Grokking AWS Certified CloudOps Engineer – Associate (SOA C03)

IAM Access Troubleshooting Workflow

Explore a structured approach to troubleshoot IAM access denials in AWS. Understand how to collect evidence from CloudTrail, identify deny sources like SCPs and permissions boundaries, apply minimal fixes, and verify access with IAM Access Analyzer. This lesson helps you effectively resolve authorization errors while maintaining security best practices.

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A failing call is the fastest way to stay honest about what's actually broken, because it removes the guesswork that speculation invites. Here is a common AWS CLI symptom where the request clearly reached the service, but the authorization decision rejected it.

The following command attempts to upload a build artifact to S3.

C++
# AWS CLI
aws s3api put-object \
  --bucket my-team-artifacts \
  --key builds/app.tar.gz \
  --body ./app.tar.gz

The expected state is that the object uploads, but the CLI instead returns an error like this.

Shell-20
An error occurred (AccessDenied) when calling the PutObject operation: Access Denied

Before changing any policy JSON, the minimum evidence that would let this decision be reproduced needs to be captured. Without a name for the principal, the Action, the resource ARN, and the request context such as region, service endpoint, and whether the call used an assumed role session, any fix becomes guesswork and is hard to roll back safely.

The illustration below shows how a restrictive policy denies access to an S3 bucket:

Restrict access to S3
Restrict access to S3

Map the deny to a boundary

Once the principal, action, resource, and context are in hand, the next step is asking where a deny could be introduced. ...