Securing Cloud-Native Applications: A CISO’s Perspective on Broken Access Control

When we talk about security in cloud-native applications, broken access control remains one of the most dangerous vulnerabilities. The OWASP Top 10 lists it as the most prevalent security risk today, and for good reason: the impact of mismanaged permissions can lead to catastrophic outcomes like data breaches or ransomware attacks. For CISOs, addressing broken access control isn't just a technical challenge—it’s a strategic priority that touches nearly every aspect of an organization’s security posture.

As part of my job as the VP of Developer Relations in Permit.io, I consulted with dozens of CISOs and security engineers leaders, from small garage startup founders to Fortune 100 enterprise security staff. This article will try to provide the most comprehensive perspective I gathered from these chats, guiding you in considering broken access control challenges in cloud-native applications.

Understanding the Threat

At its core, broken access control occurs when unauthorized users gain access to parts of an application they shouldn’t be able to see or modify. This vulnerability can manifest in several ways: from users gaining admin privileges they shouldn’t have to attackers exploiting weak session management to move laterally within a system.

What makes this threat particularly dangerous in cloud-native environments is the complexity of modern application architectures. Microservices, third-party APIs, and distributed resources create a multifaceted ecosystem where data flows across various services. Each connection is a potential point of failure. CISOs must ensure that access control mechanisms are ironclad—every request to access sensitive data or perform critical operations must be carefully evaluated and tightly controlled.

The Three Pillars of Access Control

Addressing broken access control requires a comprehensive strategy built on three key pillars: authentication, permissions, and session management. Each plays a critical role in securing cloud-native applications:

1. Authentication: This is the first line of defense, ensuring that users are who they claim to be. Strong authentication methods like multi-factor authentication (MFA) can drastically reduce the risk of unauthorized access.
2. Permissions: Even after authentication, not all users should have equal access. Permissions dictate what authenticated users can do. In cloud-native apps, fine-grained permissions are essential to prevent privilege escalation and data leakage.
3. Session Management: Proper session management ensures that once a user is authenticated and authorized, their activities are monitored, and their access remains limited to the session’s scope. Poor session management can allow attackers to hijack sessions or escalate privileges.

Why Permissions Matter More Than Ever

While all three pillars are crucial, permissions are the backbone of modern access control. In a cloud-native environment, where services and resources are distributed across different infrastructures, managing permissions becomes exponentially more challenging. A one-size-fits-all approach, like assigning simple roles (e.g., Admin, User), isn’t sufficient. Today’s applications require a more nuanced approach to permissions management.

Fine-Grained Authorization

To prevent unauthorized access, organizations should implement fine-grained authorization models. These models allow for more precise control by evaluating multiple attributes—such as a user’s role, location, or even payment method—before granting access. This granular level of control is necessary to avoid both horizontal and vertical privilege escalation.

For example, imagine a SaaS product with different pricing tiers. A user’s access to features shouldn’t just depend on their role (e.g., admin or regular user) but also on their subscription level, which should automatically update based on their payment status in an external payment application. Implementing fine-grained permissions ensures that only users who have paid for premium features can access them, even if they have elevated roles within the system.

The Importance of Least Privilege

A critical part of permissions management is enforcing the principle of least privilege. Simply put, users should have the minimal level of access required to perform their tasks. This principle is especially important in cloud-native applications, where microservices may expose sensitive data across various parts of the system.

For example, a developer working on one service shouldn’t have full access to every service in the environment. Limiting access in this way reduces the risk of an attacker exploiting one weak point to gain broader access. It also prevents insider threats, where an internal user might misuse their privileges.

Managing Sessions to Contain Threats

While permissions control access to features and data, session management ensures that users’ activities are properly constrained during their session. Strong session management practices include limiting session duration, detecting unusual behavior, and ensuring that session tokens are tightly secured.

Session hijacking, where attackers steal a user’s session token and take over their session, is a common attack vector in cloud-native environments. Implementing session timeouts, MFA for high-risk actions, and token revocation mechanisms can help mitigate these risks.

Effective session management also includes ensuring that users cannot escalate their privileges within the session. For example, a user who starts a session with standard permissions shouldn’t be able to gain admin-level privileges without re-authenticating.

The CISO’s Role in Securing Access Control

For a CISO, the challenge of preventing broken access control goes beyond simply setting policies. It involves fostering collaboration between security teams, developers, and product managers. This ensures that access control isn’t just a checkbox in compliance reports but a living, adaptive process that scales with the organization’s needs.

A Strategic Approach to Collaboration

CISOs must ensure that developers have the resources and tools they need to build secure applications without becoming bottlenecks in the process. Traditional access control systems often put too much burden on developers, requiring them to manually write permission logic into the code. This not only slows down development, but also introduces the risk of human error.

Instead, CISOs should promote a culture of collaboration where security, development, and product teams can work together on defining and managing access control policies. By implementing automated and scalable tools, CISOs can empower teams to enforce security policies effectively while maintaining agility in the development process.

Authorization-as-a-Service

One of the most effective ways to manage permissions in a scalable and secure manner is through authorization-as-a-service solutions. These platforms can provide a centralized, no-code interface for defining and managing authorization policies, making it easier for non-technical stakeholders to be involved in the process.

By leveraging these tools, organizations can reduce their reliance on developers to manually manage permissions. This not only speeds up the process, but also ensures that permissions are consistently enforced across all services. With real-time policy updates, automated monitoring, and auditability features, authorization-as-a-service platforms allow organizations to stay agile while maintaining strong access control measures.

The flexibility of these solutions also allows for easier scaling as the application and user base grow, ensuring that permission models can evolve without requiring significant re-engineering. Additionally, having a no-code UI allows for rapid adjustments to access policies in response to changing business needs or security requirements, without creating unnecessary dependencies on development teams.

Conclusion

Preventing broken access control vulnerabilities in cloud-native applications is a critical priority for CISOs. It requires a strategic focus on fine-grained permissions, the principle of least privilege, and robust session management. Collaboration across teams and the adoption of modern tools like authorization-as-a-service platforms can greatly simplify this complex challenge, enabling organizations to secure their environments without sacrificing speed or flexibility.

By addressing these areas, CISOs can help ensure that their organizations remain resilient to access control vulnerabilities while empowering their teams to manage permissions effectively and securely.

This article was shared as part of DZone's media partnership with KubeCon + CloudNativeCon.

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