ABAC: Attribute-based access control with AWS IAM and Tags

In today’s digital landscape, protecting sensitive data is critical and the data controls are becoming more dynamic and less static.

With cloud technology it’s essential to implement effective access control mechanisms to safeguard data and ensure data compliance with industry regulations. Attribute-based access control (ABAC) is an access control model that can helps achieve this goal.

Let’s take a look at how ABAC can be leveraged in AWS IAM and why it’s an important security measure for any businesses, especially when dealing with data compliance.

ABAC Defined

ABAC is an access control model that uses attributes to determine whether a user or entity should be granted access to a resource. Attributes can be any information that can be associated with a user, such as roles, group membership, location, time, and more. ABAC provides fine-grained access control, enabling organizations to define access policies that take into account specific attributes of users or entities.

AWS TAGS Defined

Tags are metadata that can be added to resources in cloud environments to help categorize, organize, and manage them. Tags are key-value pairs that are attached to resources, providing additional information about the resource. Tags can be added to a wide range of resources in cloud environments, including virtual machines, storage, networking components, and more.

In cloud environments, tags can be used for a variety of purposes, including:

1. Cost management: Tags can be used to track costs associated with specific resources, allowing organizations to better manage and optimize their cloud spending.
2. Resource categorization: Tags can be used to categorize resources based on different attributes, such as environment, application, or project. This can help organizations better organize their resources and make it easier to manage them.
3. Access control: Tags can be used as attributes in access control policies to grant or deny access to resources. This enables organizations to define more granular access control policies based on tags, allowing only authorized users to access specific resources.
4. Compliance: Tags can be used to ensure compliance with industry regulations and company policies. For example, tags can be used to indicate that a resource contains sensitive data, allowing organizations to ensure that only authorized users can access it.

AWS IAM & ABAC

AWS Identity and Access Management (IAM) is a cloud-based service that enables you to manage user access to AWS resources. IAM provides several access control mechanisms, including user-based policies and resource-based policies. ABAC can be used in IAM by leveraging the AWS Security Token Service (STS) to pass?attributes to IAM policies.

Using tags in ABAC allows for more granular access control by providing additional context to determine whether a user should be granted access to a resource.

For example, imagine an organization has a production environment and a development environment, and wants to restrict access to production resources only to users with a specific tag, such as “environment:production”. With ABAC, the organization can create an access control policy that allows access to production resources only if the user has the “environment:production” tag.

Here would be an example of a policy that leverages that tag:

“Version”: “2012–10–17”,

“Statement”: [

{

“Sid”: “AllowReadAccessToProductionObjects”,

“Effect”: “Allow”,

“Principal”: “*”,

“Action”: “s3:GetObject”,

“Resource”: “arn:aws:s3:::my-production-bucket/*”,

“Condition”: {

“StringEquals”: {

“s3:ExistingObjectTag/environment”: “production”

}

}

}

]

}{        

In this policy, the?Sid?field specifies a descriptive name for the policy statement. The?Effect?field specifies whether the policy allows or denies access. The?Principal?field specifies the AWS account, IAM user, or role that the policy applies to. In this example, the?Principal?field is set to?*, which means that any authorized user can have read access to the objects.

The?Action?field specifies the S3 action that the policy applies to. In this example, the?Action?field is set to?s3:GetObject, which allows users to retrieve objects from the bucket.

The?Resource?field specifies the S3 bucket and object that the policy applies to. In this example, the?Resource?field is set to?arn:aws:s3:::my-production-bucket/*, which allows read access to all objects in the?my-production-bucket?S3 bucket.

The?Condition?field specifies the conditions that must be met for the policy to apply. In this example, the?Condition?field specifies that the?environment?tag must be set to?production?for the policy to apply. This ensures that only objects with the?environment:production?tag can be read by authorized users.

Overall, this policy allows any authorized user to have read access to objects in the?my-production-bucket?S3 bucket, but only if the objects have the?environment:production?tag set.

To use tags in ABAC in AWS IAM, there are a few steps to follow:

1. Add tags to IAM entities: Tags can be added to IAM entities such as users, roles, and policies. Tags can be added manually or automatically using AWS services such as AWS Resource Groups Tagging API.
2. Define access control policies based on tags: Using tags, access control policies can be defined to grant or deny access to specific resources based on tags. Policies can be defined at the user, group, or resource level.
3. Test access control policies: Access control policies should be tested to ensure they are working correctly. This can be done by testing access to resources with and without specific tags to verify that access control policies are being enforced.

By using tags in ABAC, organizations can define more granular access control policies and improve security posture. Additionally, tags can be used for cost management and resource categorization, providing additional benefits beyond access control.

When using ABAC in AWS IAM, attributes can be obtained from several sources, including identity providers (IdPs), user directories, and Tags that can define custom attributes.

For example, an IdP can provide attributes such as user location, job title, and department. These attributes can be used to define policies that grant or deny access to specific resources. Similarly, user directories can provide attributes such as group membership and user roles, which can be used to define policies.

Value add proposition of ABAC

ABAC provides several benefits when used in AWS IAM, including:

1. Granular Access Control: ABAC enables organizations to define fine-grained access control policies based on attributes. This provides a more precise way to control access to resources, reducing the risk of unauthorized access.
2. Flexibility: ABAC provides flexibility in defining access control policies. Policies can be defined based on any attribute, including user location, time of day, user roles, and more. This enables organizations to tailor access control policies to their specific needs.
3. Compliance: ABAC can help organizations achieve compliance with industry regulations, such as HIPAA and PCI DSS. ABAC enables organizations to define policies that ensure access to sensitive data is limited to authorized personnel only.
4. Scalability: ABAC is highly scalable and can be used to manage access control for large, complex environments. With ABAC, policies can be defined once and applied across multiple resources, reducing the administrative burden of managing access control.

Conclusion

ABAC is an important security measure that can help organizations protect sensitive data and achieve compliance with industry regulations.

When used in AWS IAM, ABAC provides fine-grained access control based on attributes, enabling organizations to define policies that are tailored to their specific needs. With the flexibility, scalability, and compliance benefits of ABAC, it’s an effective way to manage access control in cloud environments. As more businesses move to the cloud, ABAC is becoming an essential tool for securing data and ensuring compliance.

What if I don't use ABAC as my access control model are others available?

If you didn't use ABAC, you might use other access control models such as Role-Based Access Control (RBAC) or Mandatory Access Control (MAC).

RBAC is a popular access control model that grants permissions based on a user's role or job function within an organization. In RBAC, access is granted based on predefined roles such as "administrator", "developer", or "analyst". Users are assigned to roles, and roles are granted permissions to perform specific actions on resources. RBAC is a simpler access control model than ABAC, as it doesn't take into account individual user attributes or external factors.

MAC is a more restrictive access control model that grants permissions based on security labels or categories. In MAC, access is determined by a central security policy that enforces restrictions based on the sensitivity of the resource being accessed. MAC is typically used in highly secure environments such as government agencies or financial institutions.

While RBAC and MAC are both effective access control models, they may not provide the level of granularity and flexibility that ABAC can offer. ABAC allows for more fine-grained access control policies based on a wide range of attributes, including user attributes, resource attributes, and environmental attributes. This makes ABAC a powerful tool for securing cloud environments where access control policies need to be highly customized and adaptable to changing circumstances.

Overall, these access control models provide different levels of granularity and flexibility in enforcing security policies, and each model may be more suitable for certain use cases and environments.