'AccessDeniedException' When Calling Amazon Rekognition Despite AdministratorAccess Policy

Why AdministratorAccess doesn’t override SCPs, permission boundaries, or S3 bucket policies

Category: IAM & Permission Boundaries

Problem

Your application calls the DetectLabels API in Amazon Rekognition.

The IAM role attached to your Lambda function (or EC2 instance) has AdministratorAccess.

Yet the call fails with:

AccessDeniedException: User is not authorized to perform: rekognition:DetectLabels

The policy looks correct.
The role looks correct.
Rekognition still denies the request.

Clarifying the Issue

When AWS returns AccessDeniedException, it does not mean Rekognition is malfunctioning.

📌 It means the IAM policy evaluation engine denied the request after evaluating all applicable policies.

In AWS authorization logic:

Explicit Deny > Allow
And boundaries cap permissions before evaluation completes.

Common hidden causes include:

An Organization-level Service Control Policy (SCP) blocking Rekognition
A permission boundary restricting the role
An explicit Deny statement attached somewhere in the identity chain
Region-based condition keys preventing the call
An S3 bucket policy blocking access to the underlying image

Even AdministratorAccess cannot override these controls.

Why It Matters

In production environments, this failure can:

Break image processing pipelines
Trigger Lambda retries and cost spikes
Create confusion (“But the role is Admin!”)
Delay deployments during incident response

Most teams assume the issue is Rekognition.

It almost never is.

This is an identity boundary issue — not an AI service issue.

Key Terms

AccessDeniedException – The IAM engine rejected the request.

Service Control Policy (SCP) – An Organization-level policy that overrides account-level permissions.

Permission Boundary – A policy that defines the maximum permissions an IAM role can receive.

Explicit Deny – A policy statement that blocks access regardless of other allows.

Implicit Deny – Any action not explicitly allowed is denied by default.

Steps at a Glance

Confirm the actual execution role.
Inspect CloudTrail for policy evaluation context.
Check for SCP restrictions.
Review permission boundaries.
Search for explicit deny statements.
Validate region and condition keys.
Confirm S3 object access permissions.

Detailed Steps

Phase 1: Confirm the Identity and Inspect CloudTrail

Start by verifying the exact IAM role making the call. Do not assume the correct role is attached — confirm the ARN from Lambda logs or SDK debug output.

Next, open CloudTrail → Event History, filter for rekognition.amazonaws.com, and locate the failed event.

Examine:

errorCode
errorMessage
policyEvaluationDecisionDetails

If an SCP or boundary is involved, CloudTrail will reveal it here.

This is your ground truth.

Phase 2: Evaluate Organization Guardrails (SCPs)

If your account is part of AWS Organizations, navigate to:

Organizations → Policies → Service Control Policies.

Even if your role has AdministratorAccess, an SCP can block:

{
  "Effect": "Deny",
  "Action": "rekognition:*",
  "Resource": "*"
}

SCPs operate above the account level. They cannot be overridden by account-level policies.

If Rekognition is restricted at the Organization layer, the request will always fail.

Phase 3: Inspect Permission Boundaries

Open the IAM role and check whether a permission boundary is attached.

This is frequently overlooked.

If a boundary exists, it acts as a maximum permission ceiling.

Here is the critical nuance:

If the boundary does not explicitly allow rekognition:DetectLabels, the action becomes an implicit deny, even if AdministratorAccess allows it.

AdministratorAccess does not bypass a restrictive boundary.

Phase 4: Search for Explicit Deny Statements

Review:

Inline policies
Attached managed policies

Search specifically for "Effect": "Deny".

One explicit deny anywhere in the evaluation chain will override all allow statements.

This includes condition-based denies that may only apply in certain regions or contexts.

Phase 5: Validate Region and Condition Keys

Check for policy conditions such as:

"Condition": {
  "StringEquals": {
    "aws:RequestedRegion": "us-east-1"
  }
}

If your Rekognition call is made in a different region, it will fail.

Rekognition is region-specific. Identity policies must align with the region where the API is invoked.

Phase 6: Confirm S3 Object Access

Rekognition does not just need permission to execute the API call.

It must also read the underlying image from S3.

Confirm that the execution role has:

s3:GetObject

on the specific bucket and object.

Then inspect the S3 bucket policy.

Even if your IAM role allows s3:GetObject, a restrictive bucket policy can deny access.

Bucket policy explicit denies will override identity-based allows.

This is one of the most common hidden causes of AccessDeniedException in Rekognition workflows.

Pro Tips

AdministratorAccess does not override SCPs or permission boundaries.
Any action not explicitly allowed in a permission boundary becomes an implicit deny.
Always confirm the actual execution role ARN before debugging policies.
Use the IAM Policy Simulator for rapid validation.
Verify that Rekognition and S3 are operating in the same region.
When debugging S3-related issues, check both the IAM role and the bucket policy.

If the API call succeeds but the image cannot be retrieved, the failure still surfaces as AccessDeniedException.

Conclusion

AccessDeniedException in Rekognition with AdministratorAccess is not a paradox.

It is IAM policy evaluation working exactly as designed.

When explicit denies, SCPs, permission boundaries, or bucket policies exist, AdministratorAccess becomes irrelevant.

Troubleshoot the full identity chain — not just the attached policy.

This is a systems boundary issue.

Not an AI issue.

If you'd like, we can now move cleanly into IAM Entry #2:

InvalidS3ObjectException When Rekognition Cannot Read Image from S3 Due to Bucket Policy Conflict

Aaron Rose is a software engineer and technology writer at tech-reader.blog and the author of Think Like a Genius.

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