Continuous Access Evaluation

Continuous Access EvaluationLast Updated:  6th March 2025

Continuous Access Evaluation (CAE) in Microsoft Azure

Technical Overview

Imagine a scenario where an organisation’s security team is tasked with ensuring that access to sensitive resources is revoked the moment a user’s session becomes risky—whether due to a compromised account, a revoked token, or a change in policy. Traditional access control mechanisms often rely on token lifetimes, which can leave a gap between when a risk is detected and when access is revoked. This is where Continuous Access Evaluation (CAE) steps in, offering a dynamic and near real-time approach to access management.

CAE is a feature of Microsoft Entra ID (formerly Azure AD) that enables applications to respond to critical events and enforce access decisions without waiting for the token to expire. Unlike traditional token-based access models, where a token remains valid until its expiration, CAE allows for immediate revocation of access when certain conditions are met. This is achieved through a combination of advanced signal processing, event-driven architecture, and integration with Microsoft’s identity and security ecosystem.

Architecture

CAE operates by leveraging a combination of token introspection and event-driven notifications. Here’s how it works:

  • Token Introspection: When a user attempts to access a resource, the application checks the validity of the token against the Entra ID service. This introspection ensures that the token is still valid and adheres to the latest policies.
  • Event-Driven Notifications: CAE-enabled applications subscribe to critical events such as user account disablement, password changes, or Conditional Access policy updates. When such an event occurs, the application is notified, and access can be revoked immediately.

CAE integrates seamlessly with Microsoft’s broader security ecosystem, including Conditional Access, Microsoft Defender for Cloud, and Azure Monitor. This integration ensures that access decisions are informed by the latest threat intelligence and compliance requirements.

Scalability

CAE is designed to operate at cloud scale, supporting millions of users and applications. It leverages Microsoft’s global network of data centres to ensure low latency and high availability. The event-driven architecture ensures that access decisions are made in near real-time, regardless of the size of the organisation or the complexity of its IT environment.

Data Processing

CAE processes a wide range of signals to make access decisions. These signals include:

  • User Signals: Account disablement, password changes, or multi-factor authentication (MFA) failures.
  • Device Signals: Device compliance status, location changes, or suspicious activity.
  • Environment Signals: Changes in Conditional Access policies, IP reputation, or session risk scores.

These signals are processed in real-time, enabling organisations to enforce granular access policies that adapt to changing conditions.

Integration Patterns

CAE can be integrated into a wide range of applications and services. Common integration patterns include:

  • Custom Applications: Developers can use the Microsoft Authentication Library (MSAL) to enable CAE in their applications.
  • Microsoft 365: CAE is natively supported in Microsoft 365 applications, ensuring secure access to email, documents, and collaboration tools.
  • Third-Party Applications: CAE can be extended to third-party applications through OpenID Connect and OAuth 2.0 protocols.

Advanced Use Cases

CAE is particularly valuable in scenarios where security and compliance are paramount. Examples include:

  • Zero Trust Architecture: CAE supports the principles of Zero Trust by ensuring that access is continuously evaluated based on the latest signals.
  • Incident Response: Security teams can use CAE to immediately revoke access to compromised accounts or devices.
  • Regulatory Compliance: Organisations in regulated industries can use CAE to enforce strict access controls and audit trails.

Business Relevance

In today’s threat landscape, where cyberattacks are becoming increasingly sophisticated, organisations cannot afford to rely on static access control mechanisms. CAE addresses this challenge by providing a dynamic and proactive approach to access management. Here’s why it matters:

  • Enhanced Security: By enabling real-time access revocation, CAE reduces the risk of data breaches and unauthorised access.
  • Improved User Experience: CAE minimises disruptions by allowing users to maintain access as long as their session remains compliant.
  • Cost Efficiency: By automating access decisions, CAE reduces the administrative overhead associated with manual access reviews and policy updates.

For organisations adopting a Zero Trust strategy, CAE is a critical component that ensures access decisions are always aligned with the latest security and compliance requirements.

Best Practices

To maximise the benefits of CAE, organisations should follow these best practices:

  • Enable CAE for Critical Applications: Prioritise enabling CAE for applications that handle sensitive data or are frequently targeted by attackers.
  • Integrate with Conditional Access: Use Conditional Access policies to define the conditions under which access is granted or revoked.
  • Monitor and Audit: Use tools like Azure Monitor and Log Analytics to track access events and identify potential security gaps.
  • Educate Users: Train users on the importance of secure access practices and how CAE enhances their security.

Relevant Industries

CAE is particularly beneficial for industries that require stringent security and compliance measures. These include:

  • Financial Services: Protect sensitive customer data and comply with regulations like PCI DSS and GDPR.
  • Healthcare: Secure patient data and meet HIPAA requirements.
  • Government: Ensure secure access to classified information and comply with national security standards.
  • Retail: Protect payment systems and customer data from cyber threats.

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