AWS IAM Permissions

AWS IAM Permissions are the fine-grained authorizations that specify which actions an identity (user, group, or role) can perform on specific AWS resources. They form the foundation of AWS's access control system, allowing organizations to implement the principle of least privilege across their cloud environments.

What are IAM Permissions?

IAM Permissions are access control statements implemented as JSON policy documents attached to IAM identities. Each statement contains essential elements: an Effect ("Allow" or "Deny"), Actions (specific API operations), Resources (AWS resources targeted), and optional Conditions (contextual requirements). Unlike traditional role-based systems, AWS IAM employs attribute-based access control, enabling more dynamic permissions based on user, resource, and environmental attributes.

How IAM Permissions Work

IAM permissions operate through JSON policy documents attached to identities (users, groups, roles) or resources. A policy document contains one or more statements, each defining a specific permission. Here's a simple example:

json
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "s3:GetObject",
      "Resource": "arn:aws:s3:::example-bucket/*"
    }
  ]
}

This policy allows the identity to retrieve objects from the specified S3 bucket. The permission model is additive, with explicit denies taking precedence over allows. When a principal makes a request to AWS, the authorization system evaluates all applicable policies to determine whether the request should be allowed or denied.

AWS IAM uses a deny-by-default model, meaning that access to resources is denied unless explicitly allowed through permissions. This approach ensures that new AWS services or API actions aren't automatically accessible without deliberate authorization.

Types of IAM Permission Policies

AWS IAM supports several types of policies that work together to define permissions:

Policy TypeAttached ToPrimary Purpose
Identity-based PoliciesUsers, groups, rolesControl what actions an identity can perform
Resource-based PoliciesAWS resourcesControl who can access a specific resource
Permission BoundariesUsers and rolesSet maximum permissions an identity can have

These are the main policy types you'll encounter when working with AWS IAM. For comprehensive information about all policy types, including Service Control Policies and Session Policies, refer to the AWS IAM Policy Types documentation.

Core Permission Concepts

The IAM permissions model revolves around six key elements: the Principal (user, role, or service) requests access to specific Resources (identified by ARNs) to perform Actions (API operations like s3:GetObject). The system handles Authentication (verifying identity via credentials) and Authorization (evaluating policies to permit/deny access), while Conditions enable context-based restrictions (time, IP, MFA). Understanding these components is essential for crafting effective IAM policies.

IAM Permissions in Email Infrastructure

For AWS-based email systems like those using Amazon SES, carefully designed IAM permissions are essential for security and operational integrity:

  • Email Sending Permissions such as ses:SendEmail and ses:SendRawEmail control who can send messages. These can be scoped to specific verified identities to control which domains and email addresses can be used for sending.

  • Configuration Management Permissions like ses:CreateConfigurationSet and ses:UpdateConfigurationSetEventDestination determine who can modify SES settings, which should typically be limited to administrative users.

  • Notification Processing Permissions enable systems to process bounce and complaint feedback through permissions like sns:Subscribe and sns:Receive.

  • Monitoring Permissions such as ses:GetSendStatistics and cloudwatch:GetMetricData allow teams to track email performance without necessarily having permission to send email or change configurations.

Frequently Asked Questions

How do I view all permissions granted to a specific user or role?

The AWS IAM Access Analyzer provides policy evaluation capabilities, or you can use the AWS CLI command aws iam get-policy combined with get-policy-version to review policy contents. The IAM console also provides visual tools for examining permissions.

How do I troubleshoot permission issues?

The AWS CloudTrail service logs all API calls with details about the request, including the identity, the action requested, and whether it was allowed or denied. The IAM console includes a policy simulator to test policies before applying them.

Can permissions be temporary or conditional?

Yes, through session policies used with assumed roles and through condition elements in policies. Conditions can include time-based restrictions, source IP address requirements, resource tags, and many other attributes.

Send Consistent-looking & beautiful emails today!

Email communication is part of your product! Don't let it ruin your user's experience with your brand