Least privilege principle in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the Least Privilege Principle in cloud security?

It means giving users or systems only the minimum access rights they need to do their job, nothing more.

beginner

Why is the Least Privilege Principle important in AWS?

It reduces the risk of accidental or malicious actions by limiting what users and services can do.

intermediate

How can you implement Least Privilege in AWS?

By creating IAM policies that grant only necessary permissions and regularly reviewing them.

beginner

What is a common mistake that violates the Least Privilege Principle?

Giving users or roles full administrator access when they only need limited permissions.

intermediate

How does the Least Privilege Principle help during a security breach?

It limits what an attacker can do if they gain access, reducing potential damage.

What does the Least Privilege Principle ensure in AWS?

A Users have only the permissions they need

B Users have full admin access

C Users can access all AWS services

D Users share passwords

Least Privilege means giving only necessary permissions, not full access.

Which AWS service is primarily used to manage permissions following the Least Privilege Principle?

A AWS IAM

B Amazon S3

C Amazon EC2

D AWS CloudTrail

AWS IAM controls user and role permissions.

What is a best practice to maintain Least Privilege over time?

A Give everyone admin access

B Grant all permissions once and never change

C Regularly review and adjust permissions

D Disable logging

Regular reviews ensure permissions stay minimal and appropriate.

If a user only needs to read files from an S3 bucket, what permission should they get?

A Full S3 access

B S3 read-only access to that bucket

C No permissions

D Write access to the bucket

Read-only access limits actions to only what is needed.

How does Least Privilege help in case of compromised credentials?

A It allows attackers full control

B It disables the account immediately

C It shares credentials with others

D It limits attacker actions to minimal permissions

Minimal permissions reduce damage from compromised accounts.

Explain the Least Privilege Principle and why it is important in AWS security.

Think about giving only what is needed and nothing extra.

Describe how you would implement and maintain Least Privilege for an AWS user.

Focus on creating and updating permissions carefully.

Practice

1. What does the least privilege principle mean in AWS security?

easy

A. Users get only the permissions they need to do their job

B. Users get full access to all AWS services

C. Users share passwords to access resources

D. Users can access resources without authentication

Solution

1. Step 1: Understand the principle meaning

   The least privilege principle means giving users only the minimum permissions they need.

2. Step 2: Compare options to principle

   Only Users get only the permissions they need to do their job matches this by limiting permissions to what is needed.

3. Final Answer:

   Users get only the permissions they need to do their job -> Option A

4. Quick Check:

   Least privilege = minimal needed access [OK]

Hint: Least privilege means minimum permissions needed [OK]

Common Mistakes:

• Thinking least privilege means full access
• Confusing least privilege with no access
• Assuming password sharing is secure

2. Which IAM policy snippet follows the least privilege principle for allowing S3 read-only access to a specific bucket my-bucket?

easy

A. {\"Effect\": \"Allow\", \"Action\": [\"s3:DeleteObject\"], \"Resource\": \"arn:aws:s3:::my-bucket/*\"}

B. {\"Effect\": \"Allow\", \"Action\": \"s3:*\", \"Resource\": \"*\"}

C. {\"Effect\": \"Allow\", \"Action\": [\"s3:GetObject\"], \"Resource\": \"arn:aws:s3:::my-bucket/*\"}

D. {\"Effect\": \"Allow\", \"Action\": [\"ec2:StartInstances\"], \"Resource\": \"*\"}

Solution

1. Step 1: Identify required permissions for read-only S3 access

   Read-only means allowing only s3:GetObject on the specific bucket's objects.

2. Step 2: Match policy actions and resources

   {\"Effect\": \"Allow\", \"Action\": [\"s3:GetObject\"], \"Resource\": \"arn:aws:s3:::my-bucket/*\"} allows only s3:GetObject on my-bucket objects, following least privilege.

3. Final Answer:

   Policy allowing only s3:GetObject on my-bucket objects -> Option C

4. Quick Check:

   Least privilege = specific action + resource [OK]

Hint: Allow only needed actions on specific resources [OK]

Common Mistakes:

• Using wildcard * for all actions or resources
• Allowing delete or write actions unnecessarily
• Granting permissions for unrelated services

3. Given this IAM policy snippet, what is the effective permission granted?

{
  "Effect": "Allow",
  "Action": ["s3:PutObject", "s3:GetObject"],
  "Resource": "arn:aws:s3:::example-bucket/*"
}

medium

A. Denies all access to example-bucket

B. Allows uploading and downloading objects only in example-bucket

C. Allows full access to all S3 buckets

D. Allows deleting objects in example-bucket

Solution

1. Step 1: Analyze actions in the policy

   The policy allows s3:PutObject (upload) and s3:GetObject (download) actions.

2. Step 2: Check resource scope

   The resource is limited to objects inside example-bucket, so permissions apply only there.

3. Final Answer:

   Allows uploading and downloading objects only in example-bucket -> Option B

4. Quick Check:

   Actions + resource = upload/download in example-bucket [OK]

Hint: Check actions and resource ARN carefully [OK]

Common Mistakes:

• Assuming delete permission is included
• Thinking permissions apply to all buckets
• Confusing allow with deny

4. You created an IAM policy to allow only starting EC2 instances but users report they can also stop instances. What is the likely mistake?

medium

A. The users have an additional policy granting stop permissions

B. The policy includes both ec2:StartInstances and ec2:StopInstances actions

C. The policy is attached to the wrong user

D. The policy uses wildcard * for all EC2 actions

Solution

1. Step 1: Understand the reported behavior

   Users can stop instances, which is not intended by the new policy.

2. Step 2: Identify possible causes

   If the policy only allows starting, but users can stop, they likely have another policy granting stop permissions.

3. Final Answer:

   Users have an additional policy granting stop permissions -> Option A

4. Quick Check:

   Multiple policies combine permissions [OK]

Hint: Check all policies attached to users [OK]

Common Mistakes:

• Assuming one policy overrides others
• Not checking group or role policies
• Ignoring policy wildcards

5. You want to apply the least privilege principle for a developer who needs to manage Lambda functions but only in the dev-environment. Which approach is best?

hard

A. Give the developer admin access to manage Lambda

B. Create an IAM policy allowing all Lambda actions on all functions

C. Attach the AWS managed policy AWSLambdaFullAccess to the developer

D. Create an IAM policy allowing only Lambda actions on functions with resource ARN containing dev-environment

Solution

1. Step 1: Identify the scope of access needed

   The developer needs to manage Lambda functions only in the dev-environment.

2. Step 2: Apply least privilege by limiting actions and resources

   Create an IAM policy allowing only Lambda actions on functions with resource ARN containing dev-environment restricts Lambda actions to only functions in dev-environment, minimizing risk.

3. Step 3: Evaluate other options

   Options B, C, and D grant broader access than needed, violating least privilege.

4. Final Answer:

   Create an IAM policy allowing only Lambda actions on functions with resource ARN containing dev-environment -> Option D

5. Quick Check:

   Least privilege = limit actions + resource scope [OK]

Hint: Limit permissions by resource tags or names [OK]

Common Mistakes:

• Using broad AWS managed policies
• Granting admin or full access unnecessarily
• Ignoring resource-level restrictions