How to Fix AWS CloudFront 403 Access Denied Error

In this tutorial, you'll learn about How to Fix AWS CloudFront 403 Access Denied Error. We cover key concepts, practical examples, and best practices to help you understand and apply this topic effectively.

You access a CloudFront URL and get 403 Access Denied — CloudFront cannot fetch the content from the origin or the request is unauthorized.

Step-by-Step Fix

1. Check the origin configuration

aws cloudfront get-distribution --id E1234567890ABC

2. Update S3 bucket policy for OAI

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {"AWS": "arn:aws:iam::cloudfront:user/CloudFront Origin Access Identity E1234567890ABC"},
            "Action": "s3:GetObject",
            "Resource": "arn:aws:s3:::my-bucket/*]
        }
    ]
}

3. Create or update an Origin Access Identity

aws cloudfront create-cloud-front-origin-access-identity --cloud-front-origin-access-identity-config CallerReference=my-oai,Comment=my-oai

4. Update the distribution to use OAI

aws cloudfront update-distribution --id E1234567890ABC --distribution-config file://dist-config.json

5. Invalidate the CloudFront cache

aws cloudfront create-invalidation --distribution-id E1234567890ABC --paths "/*"

Expected output:

{
    "Invalidation": {
        "Id": "I1234567890ABC",
        "Status": "InProgress"
    }
}

6. Check signed URLs or signed cookies

If using restricted access, generate a signed URL:

aws cloudfront sign --url https://d123.cloudfront.net/file.pdf --key-pair-id K12345678 --private-key-file-path pk.pem --date-less-than 2026-12-31

Common Mistakes

Prevention

• Use Origin Access Control (OAC) instead of OAI for better security.
• Set appropriate Cache-Control headers.
• Monitor CloudFront logs for 403 patterns.
• Use AWS WAF for additional access control.

Common Mistakes with CloudFront 403

1. Forgetting that lazy evaluation defers computation until the value is forced, causing space leaks with unevaluated thunks
2. Using return to exit a function early instead of wrapping a pure value in the monad
3. Mixing let bindings with <- bindings in do notation, producing type errors

These mistakes appear frequently in real-world AWS code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

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