What is role-based access?

Key takeaways:

  • Role-based access in AWS allows temporary permissions without needing access keys, relying on roles that define actions and resources for entities like users or services.

  • IAM roles use two key policies: a permissions policy (defining actions) and a trust policy (defining who can assume the role), supported by AWS Security Token Service (STS) for temporary security credentials.

  • Types of roles include service roles (for AWS services), delegated roles (trusting other accounts), and federated roles (for single sign-on with external authentication like SAML).

Role based access gives an entity the right to perform an action based on the role it’s assigned to. This entity can be a person or a machine. Roles are used for categorizing, authorizing, and authenticating.

Role-based access gives us two main advantages:

  1. There is no need for access keys.

  2. Role-based access can be given temporarily.

The permissions given to a role need not be associated with any user or group.

Example use case for AWS role-based access

Suppose you have an application that needs to access the Amazon S3 bucket for config. For security reasons, you would not want to store the access key in the application itself. You can create a role that allows this service to access the S3 bucket. At runtime, the service assumes the role, and AWS returns temporary security credentials to the user.

This Answer will focus on role-based access in AWS.

permissions_policy.json
trust_policy.json
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "VisualEditor0",
"Effect": "Allow",
"Action": [
"s3:GetLifecycleConfiguration",
"s3:GetBucketTagging",
"s3:GetInventoryConfiguration",
"s3:GetObjectVersionTagging",
"s3:ListBucketVersions",
"s3:GetBucketLogging",
"s3:ListBucket",
"s3:GetAccelerateConfiguration",
"s3:GetBucketPolicy",
"s3:GetObjectVersionTorrent",
"s3:GetObjectAcl",
"s3:GetEncryptionConfiguration",
"s3:GetBucketObjectLockConfiguration",
"s3:GetIntelligentTieringConfiguration",
"s3:GetBucketRequestPayment",
"s3:GetObjectVersionAcl",
"s3:GetObjectTagging",
"s3:GetMetricsConfiguration",
"s3:GetBucketOwnershipControls",
"s3:GetBucketPublicAccessBlock",
"s3:GetBucketPolicyStatus",
"s3:ListBucketMultipartUploads",
"s3:GetObjectRetention",
"s3:GetBucketWebsite",
"s3:GetBucketVersioning",
"s3:GetBucketAcl",
"s3:GetObjectLegalHold",
"s3:GetBucketNotification",
"s3:GetReplicationConfiguration",
"s3:ListMultipartUploadParts",
"s3:GetObject",
"s3:GetObjectTorrent",
"s3:GetBucketCORS",
"s3:GetAnalyticsConfiguration",
"s3:GetObjectVersionForReplication",
"s3:GetBucketLocation",
"s3:GetObjectVersion"
],
"Resource": [
"arn:aws:s3:::test-bucket",
"arn:aws:s3:::*/*"
]
},
{
"Sid": "VisualEditor1",
"Effect": "Allow",
"Action": [
"s3:ListStorageLensConfigurations",
"s3:ListAccessPointsForObjectLambda",
"s3:GetAccessPoint",
"s3:GetAccountPublicAccessBlock",
"s3:ListAllMyBuckets",
"s3:ListAccessPoints",
"s3:ListJobs"
],
"Resource": "*"
}
]
}

IAM policy types in AWS

While creating a role, you need to specify two policies:

  • Permissions policy: Define what actions and resources the role can use.

  • Trust policy: Define who is allowed to assume a role.

You need to define both of these policies.

An example of a role-based policy type in AWS is shown below. As you can see, the permission_policy.json allows all permissions to the S3 bucket. The trust_policy.json allows the EC2 machine to assume the role. So, when you attach this role to an Amazon EC2 instance, that instance will be able to perform operations on the specified S3 bucket.

Role-based access control (RBAC) is a widely adopted access control model that grants permissions based on a user’s role within an organization. Instead of assigning individual permissions to users, RBAC assigns users to roles, and each role has a set of predefined permissions. This simplifies management and enhances security by controlling access based on roles rather than specific users. The access control models like RBAC help organizations ensure that users have appropriate access to systems and data based on their responsibilities.

Key components of role-based access control

Here are some of the core components of RBAC:

  • Roles: A set of permissions defining what actions can be performed.

  • Users: Individuals assigned to specific roles.

  • Permissions: The actions that a role is allowed to perform, such as read, write, or modify.

  • Role assignments: The association of users with specific roles. The combination of permissions and roles in access control ensures that users can only access resources necessary for their role.

How does role-based access work?

RBAC works by assigning users to predefined roles, each of which has a set of permissions. When a user tries to access a resource, the system checks the user’s role to determine whether they have the necessary permissions. For instance, in an organization, a role-based access mechanism might allow only administrators to modify system settings, while regular employees can only view them. User roles in RBAC are typically aligned with job functions, such as “manager,” “developer,” or “HR personnel.”

Security Token Service (STS)

The IAM roles rely on the Security Token Service. The AWS STS acts as the middleman that validates the user and serves tokens—it provides temporary security credentials. These short-term credentials can last anywhere between 15 minutes and 36 hours and are dynamically assigned as requested. Since these credentials are only assigned when requested and are short-term, there is no need to rotate or revoke the password or access keys.

Role-based access vs. other access control models

RBAC is often compared to other access control models like attribute-based access control (ABAC) and discretionary access control (DAC):

  • RBAC vs. ABAC: ABAC grants permissions based on user attributes, such as location or device, while RBAC focuses on roles.

  • RBAC vs. DAC: DAC allows resource owners to decide who can access their resources, while RBAC centralizes access decisions through role assignments. Each model has its strengths, but role-based access is ideal for organizations that prioritize simplicity and control over who can access what.

Implementing role-based access in an organization

To implement RBAC effectively, follow these steps:

  1. Define roles: Identify key roles within the organization, such as admin, employee, or contractor.

  2. Assign permissions to roles: Determine what each role can do within the system, such as accessing files or modifying records.

  3. Assign users to roles: Based on job responsibilities, assign users to appropriate roles.

  4. Monitor and audit: Regularly review role assignments and permissions to ensure they remain aligned with organizational changes. Following role-based access control best practices ensures a smooth and secure implementation.

Use cases of role-based access control

RBAC use cases are found in various industries and applications:

  • Healthcare: Ensuring doctors have access to patient records while limiting administrative staff to billing information.

  • Finance: Granting auditors read-only access to financial records while allowing managers to approve transactions.

  • IT: Defining access controls where developers can access development environments, but only administrators can deploy to production. These real-world applications of RBAC highlight its versatility in controlling access across different sectors.

Types of roles

Following are the types of roles available that you need to know:

Service role

AWS service assumes this role to perform actions on your behalf. Service roles only work within an AWS account. A type of service role can be for an EC2 instance, where the role is attached to an EC2 instance and made available to its applications. Another type of service role is the service-linked role, where a role provides all the permissions required by a service.

In the above diagram, we have a webapp that is running in an EC2 instance. Let’s say that the webapp needs to access the Amazon S3 bucket; the EC2 instance will then connect to an AWS STS to get temporary security credentials for a role that has permission to access the S3 bucket. These credentials will be stored in something known as the instance profile on the EC2 instance. The webapp can then connect to this local store to get the credentials at runtime and access the S3 instance.

Delegated role

Permissions are granted to others to access the resources you control. A trust relationship is set up between your account as a trusting account and other trusted accounts. Trusted accounts can either be the same account or other accounts within or outside of your organization.

Federated role

This allows for single sign-on. The federated role can use various authentication engines, such as SAML 2.0 and OpenID Connect.

The above diagram shows an example of a federated role. The resources are in the AWS. For the sake of this diagram, the web providers or the SAML providers are outside AWS. The user validates with these providers and then calls STS with AssumeRolewithWebIdentity. It then gets temporary credentials to access the Amazon resources.

Best practices

  • Always use IAM roles for applications instead of creating IAM users. These make your applications more secure.

  • Use roles for corporate identities instead of creating multiple identities. This allows the user to use their existing credentials for Amazon access.

  • Use roles for web identities that require temporary access. This allows you to let the end-users use their existing web accounts to access your resources.

Benefits of role-based access control

Following are some of the benefits of using RBAC:

  1. Simplified management: Managing permissions through roles reduces the complexity of assigning individual permissions to each user.

  2. Improved security: Advantages of RBAC include restricting access based on job responsibilities and minimizing the risk of unauthorized access.

  3. Compliance and audit readiness: By enforcing consistent policies, RBAC makes it easier to comply with regulations and audit access control activities.

  4. Scalability: Roles can be easily assigned and modified as organizations grow, making role-based access suitable for large and evolving environments.

Security considerations for role-based access

While implementing RBAC, it is important to consider the following:

  • Least privilege principle: Ensure that roles are designed to grant the minimum level of access necessary for users to perform their tasks.

  • Regular reviews: Conduct periodic audits of role assignments and permissions to detect anomalies or unauthorized access.

  • Segregation of duties: Split critical functions across different roles to prevent fraud or errors. For example, separate the roles of developers and security auditors.

Implementing these RBAC security practices helps organizations minimize risks with RBAC by ensuring that access is tightly controlled and regularly reviewed.

Common challenges in managing role-based access control

  1. Role explosion: As organizations grow, so does the number of roles, leading to management complexity.

  2. Inconsistent role definitions: Without standardization, roles may overlap, leading to confusion over who has access to what.

  3. Auditing difficulties: Tracking and auditing roles and permissions can become difficult if not regularly maintained.

Managing these RBAC challenges requires ongoing monitoring, refinement, and ensuring roles are well-defined and aligned with organizational goals.

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Frequently asked questions

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What is the purpose of role-based access?

Role-based access control is a popular tool used by large organizations to provide employees with different levels of access according to their positions and responsibilities. This safeguards private information and guarantees that workers can only access and take activities necessary to carry out their duties.


What is the difference between user-based access and role-based access?

RBAC provides access based on roles, while ABAC evaluates access using various factors, such as action types and user or object attributes.


What is function role-based access?

An access control method called role-based access control (RBAC) establishes roles and privileges to decide whether or not to allow a user access to a resource. Roles are established according to attributes like a user’s seniority, department, location, or responsibilities.


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