Oracle Cloud Infrastructure (OCI) Identity and Access Management (IAM) traditionally follows an implicit deny model, where access is denied unless explicitly allowed. While this approach is effective, modern cloud governance often requires explicit guardrails to prevent sensitive actions—even when broad permissions exist. To address this need, OCI introduced IAM Deny Policies, enabling administrators to explicitly block specific actions and enforce stronger security controls.
What Are IAM Deny Policies?
IAM deny policies allow organizations to explicitly prohibit actions, overriding any existing allow policies. If a deny policy matches a request, the action is blocked regardless of other permissions. This capability is particularly valuable for enforcing governance standards, regulatory compliance, and operational safety in critical environments.
Deny policies are especially useful in large tenancies with multiple teams, compartments, and environments where broad access is necessary but unrestricted permissions could lead to accidental or unauthorized changes.
Key Characteristics
Explicit Opt-In
Deny policies are disabled by default and must be explicitly enabled by a tenancy administrator. Once enabled, the feature cannot be disabled, highlighting the need for careful planning before activation.
Administrator Protection
To prevent accidental lockouts, the default Administrators group in the default identity domain is exempt from deny policies. This ensures that core administrative access remains available even if restrictive deny rules are configured.
Policy Evaluation Order
During policy evaluation, deny policies take precedence over allow policies. If both apply to the same request, the deny rule always wins.
Policy Syntax Overview
Deny policies use the same structure as standard IAM policies, replacing allow with deny. This consistency makes them easy to understand and manage.
Example:
deny group DevTeam to manage bucket-family in compartment Prod
where request.operation = 'DeleteBucket'
This statement prevents the DevTeam group from deleting buckets in the production compartment, even if they have broader storage permissions.
Common Use Cases
Protecting Production Environments
Deny policies are ideal for preventing destructive actions such as deleting VCNs, databases, or object storage in production compartments.
Enforcing Separation of Duties
Organizations can restrict sensitive operations to specific teams by explicitly denying them to others, reinforcing clear responsibility boundaries.
Best Practices
Enable deny policies only after governance review and testing.
Keep deny statements narrow and condition-based to avoid unintended impact.
Regularly review deny policies as environments and teams evolve.
Document deny policies clearly to support audits and operational transparency.
Conclusion
OCI IAM Deny Policies add a powerful layer of control to cloud access management. When used thoughtfully, they help organizations protect critical resources, reduce operational risk, and enforce governance without sacrificing flexibility. As OCI environments grow in scale and complexity, deny policies become an essential tool for secure and disciplined cloud operations.
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