// Level 3 · Controls

Top 10 (2023)

The 10 most critical API-specific security risks.

API1:2023Critical

Broken Object Level Authorization

APIs tend to expose endpoints that handle object identifiers, creating a wide attack surface for object-level access control issues.

API2:2023Critical

Broken Authentication

Authentication mechanisms are often implemented incorrectly, allowing attackers to compromise authentication tokens or exploit implementation flaws.

API3:2023High

Broken Object Property Level Authorization

Combining excessive data exposure and mass assignment — exposing or allowing modification of object properties without proper authorization.

API4:2023High

Unrestricted Resource Consumption

Satisfying API requests requires resources. APIs without rate limiting are exposed to DoS and increased operational costs.

API5:2023High

Broken Function Level Authorization

Complex access-control policies with different hierarchies and groups lead to authorization flaws on administrative endpoints.

API6:2023Medium

Unrestricted Access to Sensitive Business Flows

APIs vulnerable to abuse of sensitive business flows (purchasing, posting, reservations) when automated.

API7:2023High

Server-Side Request Forgery

SSRF flaws can occur when an API fetches a remote resource without validating the user-supplied URI.

API8:2023High

Security Misconfiguration

APIs and supporting systems often contain complex configurations subject to mistakes — exposed cloud storage, misconfigured headers, etc.

API9:2023Medium

Improper Inventory Management

APIs expose more endpoints than traditional web apps, making documentation and asset inventory critical. Old/unused endpoints expand attack surface.

API10:2023High

Unsafe Consumption of APIs

Developers tend to trust data received from third-party APIs more than user input, leading to weaker security standards.