Malformed ADT floods the EHR
A lab partner sends oversized, oddly encoded PID segments. SI-10 validation at the engine quarantines messages and alerts integration — charts are not partially overwritten.
Information Input Validation
High Risk
Complex
Medium Cost
SI-10 requires checking the validity of information inputs. In healthcare, unvalidated HL7/FHIR messages, portal form fields, and device feeds can inject malicious payloads, corrupt charts, misfile results, or bypass authorization checks — harming both security and patient safety.
Control Objective
Validate syntactical and semantic integrity of inputs to systems that process ePHI so only well-formed, expected data is accepted into clinical and administrative workflows.
Implementation Guidance
- Identify high-risk input points: patient portals, APIs, interface engines, file imports, RPA bots, and device gateways.
- Enforce allow-lists, schema validation (FHIR profiles, HL7 constraints), length/type checks, and encoding controls.
- Reject or quarantine invalid messages with logging — do not silently coerce dangerous content.
- Validate file uploads (type, size, malware scan) for document management and imaging imports.
- Apply server-side validation even when UI validation exists.
- Include clinical plausibility checks where appropriate (e.g., impossible DOB) without replacing clinical judgment systems.
- Regression-test validators when interface specs change (pair with SA-11).
- Monitor validation failure rates for attack or partner misconfiguration signals.
Real-World Use Cases
How this control shows up in healthcare and HIPAA-covered environments.
Portal XSS in free-text symptoms
Input validation and encoding block script tags in a symptom field that would have executed in a clinician view.
CSV charge import with formula injection
Revenue-cycle upload validation strips active spreadsheet content and enforces column schemas before posting charges tied to patient accounts.
Best Practices
- Schema validation at trust boundaries.
- Server-side enforcement always.
- Quarantine + alert on failures.
- Cover interfaces and batch imports.
- Tune false positives with partner onboarding.
- Log enough context for AU review without excess ePHI in SIEM.
Common Gaps & Violations
- Interface engine set to “accept all.”
- Only client-side HTML5 checks on portals.
- Binary uploads unscanned into ECM.
- Validation errors ignored in dashboards.
- FHIR APIs without profile enforcement.
Required Documentation
- Information input validation standard (SI-10)
- Inventory of critical input points
- Validation rules / schemas for major interfaces
- Quarantine and exception handling procedures
- Monitoring / alert configuration evidence
How to Test & Validate
- Sample an interface for schema validation enabled.
- Attempt (in test) malformed input; confirm reject/quarantine.
- Review portal server-side validation for authZ IDs and fields.
- Check file upload controls on an ePHI document path.
- Inspect logs/alerts for validation failure handling.
Audit Considerations
Input validation supports integrity and malware defenses. Assessors may probe interface and portal controls especially where BA data exchanges are high volume.
HIPAA Mapping
How this NIST control supports HIPAA Security Rule expectations.
- 164.312(c) Integrity — protect ePHI from improper alteration or destruction.
- 164.308(a)(5)(ii)(B) Protection from Malicious Software — malicious input is a common malware/delivery path.
- 164.312(b) Audit Controls — validation failures and accepted inputs should be traceable where appropriate.
- 164.306 General rules — integrity of ePHI depends on trustworthy data entry paths.
Compliance Tips
- Add validation rules to partner onboarding for every new feed.
- Alert when quarantine volume spikes — often a partner outage or attack.
- Keep validators in version control under SA-10.
Frequently Asked Questions
Is SI-10 only about stopping SQL injection?
No. It covers validity of inputs broadly — including clinical message structure, file content, and API payloads that can corrupt or misuse ePHI.
Where should validation occur for HL7?
At trust boundaries (interface engine/API gateway) before data lands in the EHR of record.
Can clinicians override validation?
Soft warnings may be appropriate clinically; security allow-lists for dangerous content should not be freely bypassable without privileged, logged exception paths.
References & Resources
- NIST SP 800-53 Rev. 5 — SI-10
- HL7/FHIR validation guidance
- Related controls: SI-7, SI-11, SA-11, AC-4, AU-2
Related Guidelines
Related controls that commonly accompany SI-10.
Need Help Implementing SI-10?
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