Direct answer
API errors should help legitimate clients understand a failure without exposing credentials, sensitive records or unnecessary implementation details. Generate safe errors with synthetic data and compare public responses with protected logs.
Choose safe error cases
Agree a small set of invalid input, missing authentication and unavailable-resource cases in a test environment. Use synthetic IDs and avoid intentionally crashing services or causing expensive operations. Record expected status and client message.
Reference: OWASP REST Security Cheat Sheet.
Inspect the public response
Compare response body, headers and redirects for stack traces, internal paths, configuration values or private records. A correlation ID can help support investigate without publishing implementation internals. Check both successful and error content types.
- Do not copy real tokens or personal data into tickets.
- Test a representative gateway and application error.
- Verify the error is generated by the intended component.
Inspect protected diagnostics
With operations staff, locate the corresponding event in the approved logs. Confirm enough context exists to investigate while secrets are redacted and access and retention are appropriate. A vague public message should not eliminate useful internal evidence.
Retest consistency
After correction, repeat the original invalid request and a valid request. Verify clients still receive actionable status and documentation, while sensitive diagnostic detail remains restricted. Include representative gateway failures and application errors, as different components can format responses differently.
Assessment limits
An exposed product name alone is not proof of exploitation. A finite error sample cannot cover all exceptions or logging destinations.
Frequently asked questions
Should every API error use the same status code?
No. Use appropriate documented status codes while avoiding sensitive or unnecessary implementation details.
Can logs contain more detail than the response?
Yes, if needed for operations and protected by access controls, retention rules and secret redaction.
Primary sources and further reading
These guides combine published security guidance with practical assessment planning. Adapt checks to the owner's policy, environment, and authorized scope.
This guide was prepared with AI assistance using the linked sources and illustrative examples. Check current vendor guidance and your environment before making changes.