How to Fix Access Denied Error in DynamoDB

The AccessDeniedException in DynamoDB happens when your AWS Identity and Access Management (IAM) role or user lacks the required permissions. To fix it, update your IAM policy to include the necessary dynamodb: actions for the table or resource you want to access.

Why This Happens

This error occurs because your AWS user or role does not have permission to perform the requested DynamoDB operation. AWS uses IAM policies to control access, and if the policy is missing or too restrictive, DynamoDB denies access.

python

import boto3

# Attempt to scan a DynamoDB table without proper permissions
client = boto3.client('dynamodb')
response = client.scan(TableName='MyTable')
print(response)

Output

botocore.exceptions.ClientError: An error occurred (AccessDeniedException) when calling the Scan operation: User: arn:aws:iam::123456789012:user/ExampleUser is not authorized to perform: dynamodb:Scan on resource: arn:aws:dynamodb:us-east-1:123456789012:table/MyTable

The Fix

Update your IAM policy to grant the necessary DynamoDB permissions. For example, add dynamodb:Scan permission on the specific table. This allows your user or role to perform the scan operation without access errors.

json

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "dynamodb:Scan"
      ],
      "Resource": "arn:aws:dynamodb:us-east-1:123456789012:table/MyTable"
    }
  ]
}

Output

No error; the scan operation returns the table items successfully.

Prevention

Always follow the principle of least privilege by granting only the permissions needed for your application. Use IAM roles with specific policies instead of broad permissions. Regularly review and update your IAM policies to avoid accidental access denial.

Use AWS IAM policy simulators to test permissions before deploying. Automate permission checks in your deployment pipeline to catch issues early.

Related Errors

• ResourceNotFoundException: Happens if the DynamoDB table does not exist or the ARN is incorrect.
• ValidationException: Occurs when the request parameters are invalid.
• ProvisionedThroughputExceededException: Happens when you exceed your table's read/write capacity.

Key Takeaways

Access Denied errors happen due to missing or insufficient IAM permissions.

Grant only the necessary DynamoDB actions in your IAM policy for your resources.

Use IAM roles and policies following the least privilege principle.

Test permissions with AWS IAM policy simulator before running your code.

Review and update permissions regularly to prevent access issues.