Tutorial / Cram Notes

Permission management is a core aspect of security and governance in AWS environments. The AWS Certified DevOps Engineer – Professional exam includes various scenarios on how to manage permissions securely. One of the advanced features for permission management in AWS Identity and Access Management (IAM) is the use of permissions boundaries.

Permissions boundaries are an advanced feature that helps delegate permission management to IAM users and roles without granting full administrative access. With permission boundaries, you can set the maximum permissions that an IAM role or user can have. This facilitates a segregation of duties — someone can manage permissions within the constraints you define, but cannot escalate privileges beyond that boundary.

How Permissions Boundaries Work

You attach a permissions boundary policy to an IAM user or role. This policy defines the maximum actions and resources the user or role can access. Even if a user’s IAM policy grants broader access, any request for action is checked against the permissions boundary. If the request violates the permissions boundary, access is denied.

Key Concepts of Permissions Boundaries

  • Principal: The user, role, or an AWS service that receives permissions.
  • Permission Boundary: A set of permissions applied to an IAM entity, which determines the maximum permissions that the entity can have.
  • IAM Policy: JSON document that explicitly lists permissions.
  • Policy Evaluation Logic: In IAM, the policy evaluation logic decides whether a request should be allowed or denied based on all the relevant policies, including the permissions boundary.

Example: Delegating User Management

Imagine a scenario where you need to allow a group of developers to manage IAM users, but you want to prevent them from granting administrative access to any user.

  1. Create a Permissions Boundary Policy:

    {
    “Version”: “2012-10-17”,
    “Statement”: [
    {
    “Effect”: “Allow”,
    “Action”: [
    “iam:CreateUser”,
    “iam:DeleteUser”,
    “iam:ListUsers”,
    // More user management actions…
    ],
    “Resource”: “*”
    }
    ]
    }

  2. Attach the Permissions Boundary to the Developers Role:

    This step limits the developers’ role so they can perform user management actions but within the boundaries defined by the policy.

  3. Create IAM Policies for User Management Tasks:

    These policies will give explicit permissions to the developers. For example, creating users, changing passwords, attaching policies to users, etc.

  4. Attach IAM Policies to the Developers Role:

    This would usually give the developers the ability to manage users as defined by the policies.

When developers attempt to perform actions, AWS checks against both their attached IAM policies and the permissions boundary. Because of the permissions boundary, they can not escalate their privileges beyond what is defined.

Using IAM Policies vs. Permission Boundaries: A Comparison

Feature IAM Policy Permissions Boundary
Maximum privileges granted Defined by the policy actions and resources Defined by the boundary actions and resources
Granting permissions Directly grants permissions to an IAM entity to perform actions on resources Defines a ceiling for the permissions an IAM entity’s policy can grant
Delegation of administration Can potentially grant full admin access Cannot exceed the boundary, prevents privilege escalation
Application Attached directly to explain what actions are allowed or denied Attached to impose an additional evaluation layer for checking maximum allowed permissions

Conclusion

By using permissions boundaries, you ensure that individuals working within your AWS account can have the necessary permissions to be productive without risking unwanted privilege escalation. This approach encourages better security practices, as it helps you to implement the principle of least privilege, giving IAM entities only the access needed to accomplish their tasks.

In summary, while preparing for the AWS Certified DevOps Engineer – Professional exam, understanding how to implement and manage permissions boundaries within IAM is fundamental to ensuring secure and flexible permissions delegation in AWS.

Practice Test with Explanation

True or False: IAM permissions boundaries set the maximum permissions that an IAM role can grant to an entity.

  • True

True

IAM permissions boundaries are used to define the maximum permissions that an IAM policy or role can grant to an IAM entity, thereby providing a way to delegate permissions management.

Which AWS service is primarily used for permission management delegation?

  • A) AWS Config
  • B) AWS Identity and Access Management (IAM)
  • C) AWS Shield
  • D) Amazon GuardDuty

B) AWS Identity and Access Management (IAM)

AWS IAM is the service used for permission management, including the delegation of permissions using features like permissions boundaries.

True or False: Permissions boundaries can be used to provide an IAM user with administration permissions without granting full AWS account access.

  • True

True

Permissions boundaries allow an account administrator to delegate certain administrative privileges to IAM users while ensuring they cannot escalate their permissions beyond the boundary.

What is the purpose of an IAM permissions boundary?

  • A) To define the resource permissions for an EC2 instance
  • B) To automatically scale IAM roles
  • C) To set the maximum permissions that a user or role can have
  • D) To encrypt data using IAM policies

C) To set the maximum permissions that a user or role can have

IAM permissions boundaries define the maximum scope of permissions for an IAM role or user, which is used to delegate permissions without granting full access to the AWS account.

True or False: IAM policies attached directly to users and roles are sufficient to restrict their permissions within defined boundaries.

  • False

False

While IAM policies can restrict permissions, permissions boundaries are specifically designed to enforce a maximum permissions limit; therefore, they are needed in addition to the direct policies to effectively manage permissions delegation.

Which IAM feature prevents privilege escalation and ensures separation of duties?

  • A) IAM Groups
  • B) IAM Access Advisor
  • C) IAM Permissions Boundaries
  • D) IAM Access Keys

C) IAM Permissions Boundaries

IAM permissions boundaries prevent users and roles from escalating their privileges beyond what has been delegated to them, thus enforcing separation of duties.

True or False: Once set, an IAM permissions boundary cannot be removed or altered.

  • False

False

IAM permissions boundaries can be updated or removed by an account administrator as needed to adjust the delegated permissions.

IAM permissions boundaries are established using which of the following?

  • A) IAM managed policies
  • B) IAM inline policies
  • C) Service control policies (SCPs)
  • D) Both A and B are correct

D) Both A and B are correct

IAM permissions boundaries can be set using either managed policies or inline policies within IAM.

True or False: A user with an attached permissions boundary can perform any AWS action as long as the boundary policy allows it and there is no explicit deny in another attached policy.

  • False

False

A permissions boundary sets the maximum permissions a user or role can have. If another policy has an explicit deny or the action isn’t allowed by both the boundary and another policy, the user cannot perform that action.

Can a user with sufficient permissions attach a permissions boundary to their own IAM user or role?

  • A) Yes, if the permissions boundary allows self-management
  • B) No, as permissions boundaries can only be set by the account root user
  • C) Yes, but only if the AWS Organizations service control policies (SCPs) allow it
  • D) Yes, if the action doesn’t breach the effect of the permissions boundary itself

D) Yes, if the action doesn’t breach the effect of the permissions boundary itself

A user with the necessary permissions can generally manage their own IAM entities, including attaching permissions boundaries as long as such actions do not exceed the permissions granted by the boundary.

True or False: When an IAM entity (user or role) performs an action, AWS checks only the permissions boundary to determine whether to allow or deny the action.

  • False

False

AWS evaluates all applicable policies (including the permissions boundary, identity-based policies, and resource-based policies) to determine whether to allow or deny an action.

Interview Questions

What is an IAM Permission Boundary in the context of AWS IAM?

IAM Permission Boundary is an advanced feature in AWS IAM that allows for the setting of the maximum permissions that an identity-based policy can grant to an IAM user or role. In essence, a permissions boundary is a policy that acts as a safeguard to prevent users and roles from gaining access to resources beyond what’s intended. It sets the outermost limits and is often used in conjunction with other policies for more granular permission control.

How do Permission Boundaries help with the Principle of Least Privilege in AWS?

Permission Boundaries help enforce the Principle of Least Privilege by ensuring that IAM users and roles can only access the resources and perform the actions that are absolutely necessary for their work. They prevent the escalation of privileges by defining the maximum permissions an entity can have, regardless of the permissions granted through other policies.

Can you explain how one might delegate administration tasks without giving away full administrative privileges using Permission Boundaries?

To delegate administration tasks without giving away full administrative privileges, an administrator can set a Permission Boundary for a user or role that outlines the specific scope of permissions they can use. This way, when administrators delegate tasks, they can attach a policy that grants the necessary permissions within the constraints set by the Permission Boundary, thus controlling the extent to which privileges can be elevated.

How would you use IAM Permission Boundaries to segregate duties in a large organization?

In a large organization, IAM Permission Boundaries can be used to segregate duties by creating different boundaries for distinct roles or departments. For instance, a boundary for the networking team might limit access to VPC-related actions, while a boundary for the development team might restrict permissions to certain EC2 instances and S3 buckets. This ensures that each team has only the access they need to perform their specific tasks and cannot interfere with other teams’ resources.

How do IAM Permission Boundaries interact with other IAM policies attached to a user or role?

IAM Permission Boundaries act as a filter on top of other IAM policies attached to a user or role. The effective permissions are the intersection of the entity’s IAM policies and the Permission Boundary; an entity can only perform an action if it’s allowed by both the entity’s policies and the boundary policy.

Give an example of a situation where you might use IAM Permission Boundaries instead of managed policies?

IAM Permission Boundaries are best used in situations where you want to delegate permission management to other users without giving them unrestricted control. For example, allowing a team lead to manage permissions of their team members without being able to grant full administrative access. This cannot be as effectively achieved using managed policies alone, as managed policies do not inherently limit the scope of permissions they can grant.

Can you deny a permission using a Permission Boundary?

No, a Permission Boundary does not explicitly deny permissions. Instead, it sets the maximum allowed permissions. If an action is not allowed by the Permission Boundary, it’s implicitly denied, even if it’s allowed by the user’s or role’s other policies.

What would happen if you don’t define a Permission Boundary for an IAM user or role?

If you don’t define a Permission Boundary for an IAM user or role, there will be no additional restrictions on what permissions can be granted through their assigned policies. The user or role can potentially be granted permissions as wide as the account’s resource and action space, subject to other existing IAM policy limits.

Is it possible to use Permission Boundaries to delegate permissions across different AWS accounts in an organization?

Yes, Permission Boundaries can be used in conjunction with AWS Organizations and Service Control Policies (SCPs) to delegate permissions across different AWS accounts in a multi-account setup. Permission Boundaries apply to individual IAM users and roles within an account, while SCPs apply to all IAM entities in member accounts.

How do you create or manage a Permission Boundary for an IAM role using the AWS Management Console?

To create or manage a Permission Boundary for an IAM role using the AWS Management Console, you navigate to the IAM role, go to the “Permissions” tab, and then click “Add Permission Boundary.” Choose the policy you want to set as the boundary, which limits the permissions for the role. This procedure sets or updates the existing Permission Boundary for that role.

What is the effect of removing a Permission Boundary from an IAM user or role?

Removing a Permission Boundary from an IAM user or role removes the restriction on the maximum permissions they can have. Consequently, their effective permissions may increase because they’re now dictated solely by the user or role’s actual identity-based IAM policies without the overarching limits set by the Permission Boundary.

How might you audit the use of IAM Permission Boundaries within an AWS environment?

To audit the use of IAM Permission Boundaries within an AWS environment, you can use AWS CloudTrail logs to track API calls that create, modify, or delete Permission Boundaries. Additionally, you can use the IAM console or CLI commands to list all IAM users or roles with attached Permission Boundaries. AWS Config can also help to track changes and compliance of IAM entities with company policies regarding Permission Boundaries.

0 0 votes
Article Rating
Subscribe
Notify of
guest
27 Comments
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
آیلین موسوی

Great blog post! Permission management through IAM permissions boundaries is a game-changer for DevOps.

Ratimir Sharko
6 months ago

Thanks, this was really helpful for my exam prep!

Abhinav Nair
6 months ago

Can anyone clarify how permissions boundaries differ from regular IAM policies?

VÃ¥rin Tyldum
6 months ago

Bookmarking this for later. Thanks!

Shrinidhi Tipparti
6 months ago

Fantastic explanation on IAM permission boundaries!

Abhinav Nair
6 months ago

What are some common use cases for using IAM permissions boundaries?

Vicki Thomas
6 months ago

I’ve passed my AWS Certified DevOps Engineer exam, thanks to resources like this!

Thor Selvik
7 months ago

Very informative. Thank you!

27
0
Would love your thoughts, please comment.x
()
x