CWE-638

Not Using Complete Mediation

Weakness Description

The product does not perform access checks on a resource every time the resource is accessed by an entity, which can create resultant weaknesses if that entity's rights or privileges change over time.

Potential Mitigations

Architecture and Design

Invalidate cached privileges, file handles or descriptors, or other access credentials whenever identities, processes, policies, roles, capabilities or permissions change. Perform complete authentication checks before accepting, caching and reusing data, dynamic content and code (scripts). Avoid caching access control decisions as much as possible.

Architecture and Design

Identify all possible code paths that might access sensitive resources. If possible, create and use a single interface that performs the access checks, and develop code standards that require use of this interface.

Common Consequences

IntegrityConfidentialityAvailabilityAccess ControlOther
Gain Privileges or Assume IdentityExecute Unauthorized Code or CommandsBypass Protection MechanismRead Application DataOther

A user might retain access to a critical resource even after privileges have been revoked, possibly allowing access to privileged functionality or sensitive information, depending on the role of the resource.

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