Control statement
- a.Generate error messages that provide information necessary for corrective actions without revealing information that could be exploited; and
- b.Reveal error messages only to [Organization-defined: personnel or roles].
Discussion
Organizations consider the structure and content of error messages. The extent to which systems can handle error conditions is guided and informed by organizational policy and operational requirements. Exploitable information includes stack traces and implementation details; erroneous logon attempts with passwords mistakenly entered as the username; mission or business information that can be derived from, if not stated explicitly by, the information recorded; and personally identifiable information, such as account numbers, social security numbers, and credit card numbers. Error messages may also provide a covert channel for transmitting information.
Organization-defined parameters
These values must be resolved through the organization’s tailoring and governance process. Bracketed parameter references in the control text identify where a decision is required.
From control text to operational evidence
Use Error Handling as a testable risk decision. Translate the official statement into accountable people, repeatable processes, configured technology, and evidence that demonstrates the outcome over time. In this family, pay particular attention to flaw remediation, malicious-code protection, monitoring, integrity, and trustworthy information handling.
Implementation workflow
- Define the control boundary, responsible owner, inherited portions, and systems or processes in scope.
- Resolve each organization-defined parameter before declaring the control implemented.
- Document how the implementation satisfies every clause of the official control statement.
- Collect evidence as a normal byproduct of operation rather than only before an assessment.
- Review exceptions, changes, and monitoring results on a risk-based cadence.
Evidence examples
- patch and remediation records
- malware protection configuration
- monitoring alerts and response records
- integrity validation and exception reports
Common failure patterns
- patch compliance hides unsupported assets
- alerts generated without response ownership
- exceptions never expire
- integrity monitoring excludes critical configurations
Questions practitioners should ask
- What risk decision is this control intended to support in this system?
- Which parts are implemented locally, inherited, shared, or not applicable—and what evidence supports that decision?
- Do the documented narrative, deployed configuration, operating process, and collected evidence agree?
- What event or threshold requires the implementation to be reviewed or changed?
Assessment objectives and methods
Show the assessment objective
- SI-11a.error messages that provide the information necessary for corrective actions are generated without revealing information that could be exploited;
- SI-11b.error messages are revealed only to [Organization-defined: personnel or roles].
Examine
- System and information integrity policy
- system and information integrity procedures
- procedures addressing system error handling
- system design documentation
- system configuration settings and associated documentation
- documentation providing the structure and content of error messages
- system audit records
- system security plan
- other relevant documents or records
Interview
- Organizational personnel responsible for information input validation
- organizational personnel with information security responsibilities
- system/network administrators
- system developer
Test
- Organizational processes for error handling
- automated mechanisms supporting and/or implementing error handling
- automated mechanisms supporting and/or implementing the management of error messages
Related controls
These relationships come from the official OSCAL catalog. They indicate useful dependencies or context, not automatic inheritance or equivalence.
Related NIST SP 800-172 requirements
These Rev. 3 requirements cite this base control or one of its enhancements as a source. The relationship does not by itself determine contractual applicability or complete implementation.
Authoritative sources
Bare Metal Cyber is an independent educational publisher and is not affiliated with or endorsed by NIST. Official control requirements and interpretations remain with NIST and the responsible authorizing organization.