Findings

Missing 500 response

Updated: June 19, 2025

Description

An endpoint is missing the definition for a 500 response. OWASP API Security recommends defining schemas for all responses, even errors. The 500 response describes what happens when a request fails with an internal server error, so it's important to define to make sure the proper JSON structure is being returned instead of leaking implementation details in backtraces.

Remediation

Add the definition for 500 responses to the endpoint.

Security Frameworks

This category combines API3:2019 Excessive Data Exposure and API6:2019 - Mass Assignment, focusing on the root cause: the lack of or improper authorization validation at the object property level. This leads to information exposure or manipulation by unauthorized parties.

Looking forward to generic implementations, developers tend to expose all object properties without considering their individual sensitivity, relying on clients to perform the data filtering before displaying it to the user.

CIS-ASG-2.3.2: CIS 2.3.2: Establish standardized error handling procedures

Put in place a consistent procedure to handle errors.

Rationale

Establishing standardized error handling procedures ensures consistency across the API, providing a uniform approach to managing and communicating errors. This improves the clarity and usefulness of error messages for developers and users, enhancing overall user experience. It also prevents revealing sensitive information that could help attackers.

Remediation
  • Improve the clarity of error messages.
  • Establish guidelines for handling errors.
  • Enforce HTTP return status compliance.
  • Update the documentation accordingly.
Audit
  • Review the documentation by inspecting the existing error format that is in place.
  • Identify potential disclosure of internal system information in error messages.
  • Assess all existing error message quality - is it comprehensive, does it correctly communicate the error.
  • Verify HTTP standards compliance, for example 404 error should be used for non-existing resources, 401/403 error codes should be used for unauthorized access and so on.

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Missing 4xx response
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