Tutorial / Cram Notes
Organizational Service Control Policies (SCPs) are a critical component in managing AWS environments, especially when it comes to ensuring that the infrastructure adheres to the compliance and security requirements of an organization. SCPs are part of AWS Organizations and offer centralized control over permissions for all accounts within your organization, ensuring that certain actions are allowed or denied across all accounts under the organization’s umbrella.
For those studying for the “AWS Certified DevOps Engineer – Professional (DOP-C02)” exam, a deep understanding of SCPs and their application in a multi-account AWS environment is essential. The exam not only covers the technical implementation of these policies but also their strategic use in an organization-wide security strategy.
What are Organizational SCPs?
Organizational SCPs are JSON policies that specify the maximum permissions for member accounts within an AWS Organization. These policies can allow or deny access to AWS services and APIs, restricting or enabling actions across all accounts or specific organizational units (OUs).
How Do SCPs Work?
SCPs work at the organization or organizational units level. They don’t grant permissions but instead act as a filter for the permissions that are already granted through identity-based policies (like IAM roles and policies) or resource-based policies.
Here’s an overview of how SCPs interact with other policies:
Operator’s Permissions = IAM Permissions ∩ Resource-Based Permissions ∩ SCPs
If IAM permissions allow an action, but an SCP denies it, then the action is denied. Conversely, if IAM permissions deny an action, SCPs cannot override this to allow the action.
SCPs Examples
Here’s a simple SCP that denies deleting Amazon EC2 instances:
{
“Version”: “2012-10-17”,
“Statement”: [
{
“Effect”: “Deny”,
“Action”: “ec2:TerminateInstances”,
“Resource”: “*”
}
]
}
And an SCP that ensures only encrypted Amazon S3 buckets can be created:
{
“Version”: “2012-10-17”,
“Statement”: [
{
“Effect”: “Deny”,
“Action”: “s3:CreateBucket”,
“Resource”: “*”,
“Condition”: {
“StringNotEquals”: {
“s3:x-amz-server-side-encryption”: “AES256”
}
}
}
]
}
Using SCPs in a Multi-account Strategy
When utilizing SCPs in a multi-account strategy, it’s essential to define policies that align with your organizational structure and governance model. For example, you can apply more permissive policies at an enterprise level, then have more restrictive policies attached to OUs or specific accounts to enforce tighter controls where needed.
Table: SCP Application Examples
| Use Case | SCP Purpose | Effect |
|---|---|---|
| Prevent Service Usage | Disallow the use of non-approved AWS services | Deny |
| Enforce Compliance | Ensure actions follow compliance standards | Deny |
| Cost Control | Limit usage of high-cost services | Deny |
| Security Baseline | Establish a base security standard across all accounts | Deny/Allow |
Best Practices for Implementing SCPs
- Least Privilege Principle: Apply the least privilege principle by starting with a restrictive set of permissions and slowly allowing additional permissions as necessary.
- Policy Testing: Before applying SCPs broadly, test the policies on a limited set of OUs or accounts to ensure they don’t disrupt legitimate activities.
- Backup Policies: Maintain backups of your SCPs and ensure you have a recovery process in case of accidental overly restrictive SCPs that could lock you out of your resources.
- Monitoring and Auditing: Integrate SCP changes and effects into your monitoring and auditing strategies. Services such as AWS CloudTrail can be used to track and record changes.
- Change Management: Implement a robust change management process for SCPs modification, including peer reviews and approvals.
By mastering Organizational SCPs, AWS Certified DevOps Engineer – Professional candidates will have the knowledge to effectively use service control policies to manage security and compliance at scale within an AWS Organization. Recognizing the impact of SCPs on your cloud landscape and the nuances of how they interact with other AWS security mechanisms is essential for securing AWS resources and managing cloud operations efficiently.
Practice Test with Explanation
True or False: Service Control Policies (SCPs) can be applied at the AWS Organization root level affecting all organizational units (OUs) and accounts.
- A) True
- B) False
Answer: A) True
Explanation: SCPs can be applied at the root level of an AWS Organization, impacting all OUs and accounts within the organization.
Which of the following is NOT a feature of Service Control Policies (SCPs)?
- A) Restrict permissions for users and roles in member accounts
- B) Enforce compliance requirements across multiple accounts
- C) Directly grant permissions to users and roles
- D) Modify permissions inherited from parent OUs or root
Answer: C) Directly grant permissions to users and roles
Explanation: SCPs are used to define the maximum permissions for organization members, they do not grant permissions but can restrict them.
True or False: SCPs prevent root users from performing actions that are denied by the policies.
- A) True
- B) False
Answer: B) False
Explanation: SCPs do not apply to the root user in a member account.
Which AWS service is used to manage Organizational SCPs?
- A) AWS IAM
- B) AWS Organizations
- C) AWS Config
- D) AWS CloudTrail
Answer: B) AWS Organizations
Explanation: AWS Organizations is the service that allows you to manage policies, including SCPs, for multiple AWS accounts.
True or False: SCPs support allow and deny statements.
- A) True
- B) False
Answer: A) True
Explanation: SCPs support both allow and deny statements, similar to IAM policies.
In which scenario would you detach an SCP from an OU in AWS Organizations?
- A) When you need to grant additional permissions to an OU
- B) When you need to restrict permissions on specific resources within an OU
- C) When you want to change the structure of OUs within your organization
- D) When you want the OU to inherit different SCPs from another parent
Answer: D) When you want the OU to inherit different SCPs from another parent
Explanation: Detaching an SCP from an OU allows that OU to inherit different SCPs, possibly from another parent OU or the root.
True or False: SCPs can be used to enforce tag-based access control across an organization.
- A) True
- B) False
Answer: A) True
Explanation: SCPs can include conditions that enforce tag-based access control, helping to ensure compliance with tagging strategies.
When an SCP is applied to an AWS account, who is responsible for ensuring the policies are effective?
- A) The AWS service teams
- B) The root user of the account
- C) The account administrators
- D) The AWS Organizations service
Answer: C) The account administrators
Explanation: Account administrators are responsible for ensuring that applied SCPs are effective and meet the organization’s requirements.
True or False: When SCPs are applied, the effective permissions are the intersection of the SCP and IAM policies.
- A) True
- B) False
Answer: A) True
Explanation: The effective permissions for a user or role are the combination (intersection) of the IAM policies and the SCPs that apply to the account.
SCPs are JSON policies that can do which of the following?
- A) Limit permissions for service actions across all accounts in an organization
- B) Force member accounts to enable specific AWS services
- C) Automatically resolve policy conflicts between IAM and SCPs
- D) Permit billing actions to be performed without limitations
Answer: A) Limit permissions for service actions across all accounts in an organization
Explanation: SCPs are JSON policies used to limit permissions for service actions across all accounts within an organization.
True or False: Once applied, SCPs cannot be edited or removed.
- A) True
- B) False
Answer: B) False
Explanation: SCPs can be edited or removed by authorized personnel, typically done as part of policy revisions or organizational changes.
What must be enabled for an organization to use SCPs?
- A) AWS Shield
- B) All features in AWS Organizations
- C) AWS IAM user access to billing information
- D) Multi-factor authentication for the root account
Answer: B) All features in AWS Organizations
Explanation: An organization must have all features enabled in AWS Organizations to utilize SCPs. This grants the full suite of capabilities including policy-based management for multiple accounts.
Interview Questions
What is an SCP in the context of AWS Organizations, and how does it relate to a DevOps Engineer’s role?
Service Control Policies (SCPs) are a type of policy that allow organizations to manage permissions in AWS. They are used to define the maximum permissions for member accounts within an organization. For a DevOps Engineer, SCPs are important for implementing and ensuring compliance with company-wide security protocols and service restrictions, alongside automating deployment and managing infrastructure at scale.
Can you describe how SCPs affect resources within an AWS account?
SCPs determine what actions principals (users, roles) within an AWS account can perform. They do not apply to resources directly but instead operate at the account or OU (Organizational Unit) level. SCPs effectively serve as guardrails that can allow or deny access to AWS services and actions across accounts, but they do not grant permissions.
How do SCPs differ from IAM policies in AWS?
SCPs are part of AWS Organizations and apply to all accounts within an organization or specific OUs, limiting the maximum permissions across those accounts. In contrast, IAM policies are attached to IAM users, groups, or roles within a single AWS account and are used to grant specific permissions to those entities. SCPs are essentially boundaries for IAM policies, as they cannot grant permissions beyond what SCPs allow.
Explain the role of SCPs in a multi-account AWS environment.
In a multi-account setup, SCPs help centrally manage permissions and enforce compliance and governance by defining what actions are allowed or denied across all accounts in an organization. They enable consistency and mitigate the risk of deploying resources that do not adhere to organizational policies.
How would you apply an SCP to a particular Organizational Unit (OU) within AWS Organizations?
To apply an SCP to an OU, you must first create or select the SCP in the AWS Organizations console, then select the targeted OU and attach the SCP to it. This process ensures that the specified policies are now enforced on all member accounts within that OU.
Can SCPs be used to enforce compliance with specific regulatory frameworks (e.g., HIPAA, GDPR)? How?
Yes, SCPs can be used to support compliance with regulatory frameworks by restricting the deployment or usage of services that might contravene such regulations. By constraining actions to a set of compliant services and actions, DevOps Engineers can ensure that their AWS environment aligns with requirements like HIPAA or GDPR.
What would happen if an SCP contradicts an IAM policy?
When an SCP contradicts an IAM policy, the SCP takes precedence, as IAM policies cannot grant permissions beyond the boundaries set by SCPs. If the SCP denies an action, the IAM policy cannot override this, regardless of the permissions it grants.
How can a DevOps Engineer use SCPs alongside AWS Config to enforce policy compliance?
A DevOps Engineer can use SCPs to set up preventive compliance rules, limiting which services and actions are allowed within the AWS environment. AWS Config can then be used to monitor and record compliance with these SCPs, and it can take automated remediation actions if configurations drift from established baselines.
What is the effect of an SCP that denies “s3:CreateBucket” across your AWS Organization?
If an SCP denies “s3:CreateBucket” across the AWS Organization, no principal (user or role) in any of the accounts under that organization will be able to create new Amazon S3 buckets, regardless of their IAM permissions. This ensures that bucket creation aligns with organizational policies.
How can SCPs aid in cost control within an AWS Organization?
SCPs can restrict the use of high-cost AWS services or limit the actions that can result in increased costs (for example, denying the ability to launch instances beyond certain types or sizes). This preemptive control can help prevent unexpected expenses and ensure adherence to budgets.
Can SCPs be layered, and if so, how does this affect their evaluation?
Yes, SCPs can be layered by attaching multiple SCPs to an account, OU, or the entire organization. When layered, all SCPs must allow an action for it to be permitted. If at least one SCP denies an action, it is denied. SCPs are evaluated conjunctively (using logical “AND” conditions) rather than disjunctively (using logical “OR” conditions).
Is it possible to exempt the root user from SCPs within an AWS Organization?
No, it is not possible to exempt the root user from SCPs. SCPs apply to all IAM users and roles, including the root user in every account under the AWS Organization. This ensures that even the most privileged account cannot perform actions that are not compliant with organizational controls and policies.
Great post on Organizational SCPs! Really helped solidify my understanding on AWS Certified DevOps Engineer – Professional concepts.
Can someone explain how SCPs can be applied to prevent IAM users from creating EC2 instances?
This blog post was extremely helpful. Thanks a lot!
I’m confused about how SCPs interact with IAM policies. Can anyone clarify?
Excellent explanation on how to attach SCPs to OUs. This will definitely help in my exam preparation.
Do we have any predefined SCPs for common use cases like compliance?
Thanks for this informative post, it’s exactly what I needed.
Can someone clarify if SCPs affect all AWS accounts in an Organization?