TL;DR
Attribute certificates add extra security to access control by verifying user attributes (like job title or department) beyond just their username and password. This guide shows how to set them up for more reliable and flexible access management.
What are Attribute Certificates?
Normally, when you log in, a system checks your username and password. Attribute certificates add another layer of trust. They’re like digital ID cards issued by a trusted authority (like HR or IT) that confirm specific things about you – your role, clearance level, etc. This means access decisions can be based on who you are in terms of these attributes, not just that you are who you say you are.
Setting up Attribute Certificates: A Step-by-Step Guide
- Choose an Attribute Authority (AA): This is the organisation responsible for issuing and managing certificates. It needs to be highly trusted.
- Examples: HR department, IT security team, a dedicated certificate service.
- The AA will define which attributes it can vouch for.
- Select a Certificate Format: Common formats include X.509 Attribute Certificates.
- X.509 is widely supported and well-understood.
- Consider compatibility with your existing infrastructure.
- Install a Public Key Infrastructure (PKI): This is the foundation for trust.
- You’ll need a Certificate Authority (CA) to sign certificates issued by the AA.
- OpenSSL is a popular tool for managing PKI:
openssl genrsa -out ca.key 2048
- Define Attributes: Work with stakeholders to determine which attributes are important for access control.
- Examples: department, job title, security clearance, project membership.
- Each attribute needs a clear definition and validation process.
- Issue Attribute Certificates: The AA creates certificates containing the user’s attributes, signed by the CA.
- This often involves an automated system triggered by changes in HR or IT systems.
- Example command (simplified):
openssl ca -config openssl.cnf -extensions v3_ca -days 365 -cert user.crt -key user.key -req -in user.csr
- Configure Access Control Systems: Modify your applications and systems to check for attribute certificates.
- This usually involves integrating with a Policy Decision Point (PDP).
- The PDP evaluates the attributes in the certificate against access control policies.
- Policy Definition: Create rules that determine access based on attributes.
- Example: “Users with ‘department’ = ‘Finance’ and ‘security clearance’ = ‘Level 2’ can access sensitive financial data.”
- Use a policy language like XACML (Extensible Access Control Markup Language).
- Testing & Validation: Thoroughly test the system to ensure it works as expected.
- Verify that certificates are issued correctly.
- Confirm that access control policies are enforced properly.
- Regularly review and update attributes and policies.
Integrating with Applications
Most applications won’t directly handle attribute certificates. You’ll need middleware or a gateway to intercept requests, verify the certificate, and pass the validated attributes to the application.
- Reverse Proxies: Nginx or Apache can be configured to check for certificates before forwarding requests.
- API Gateways: Kong, Tyk, or similar gateways provide a central point for access control.
Benefits of Attribute Certificates
- Enhanced Security: More granular access control reduces the risk of unauthorized access.
- Improved Flexibility: Easily adapt access policies without changing application code.
- Centralized Management: The AA provides a single point for managing user attributes.
- Compliance: Helps meet regulatory requirements for data security and privacy.