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AWS IAM Permission Denied — Troubleshooting Guide

Diagnose AWS authorization failures using the principal, action, resource, and policy evaluation path.

1 min readLevel: IntermediateUpdated Current
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troubleshootingAWSIAMsecurity

Troubleshooting

Start with the symptom. End with a verified fix.

What’s wrong?

An AWS API call fails with an authorization or access-denied error.

Possible causes

  1. Missing identity permission
  2. resource policy restriction
  3. explicit deny
  4. permissions boundary
  5. session policy
  6. organization control

Diagnosis

  1. Identify the principal
  2. action
  3. and resource
  4. inspect policy layers
  5. search for explicit denies
  6. confirm the actual role/session used

2 · Fix

Add the minimum required permission at the correct policy layer or remove the confirmed conflicting restriction.

Verify

Re-run the exact API operation and confirm the expected resource is affected.

3 · Prevent

Use least privilege, policy testing, clear role ownership, and documented permission boundaries.

AWS IAM Permission Denied

Treat an IAM failure as a policy evaluation problem, not simply a missing Allow.

Diagnose

  1. Identify the exact principal actually making the request.
  2. Identify the API action and resource ARN.
  3. Inspect identity policies and resource policies.
  4. Check for explicit denies and higher-level controls such as permissions boundaries or organization policies.
  5. Confirm the application is using the expected role/session.

Fix → Verify → Prevent

Change the narrowest policy that explains the failure. Re-run the exact operation, then capture the permission requirement in the relevant runbook or infrastructure definition.

Engineering companion

Learn → troubleshoot → design → prepare → test

Explore the knowledge graph →
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troubleshootingAWSIAMsecurity