MIME Parsing Checklist for Healthcare and Compliance

Ensure a signed BAA is in place and map how PHI enters via SMTP, flows through parsing, storage, and webhook delivery. Keep the data flow diagram current for audits and risk assessments.

Set rules for identifying PHI in headers, bodies, and attachments, then redact or tokenize before exposing JSON to non-clinical systems. Document exceptions and approval workflows.

Limit JSON output to only the fields required for the clinical workflow, excluding extraneous headers or content. This reduces breach impact and simplifies downstream controls.

Set retention aligned to policy and state law, with automated deletion and legal hold exceptions. Separate operational telemetry from PHI-bearing data for shorter retention where possible.

Decide on dedicated VPC or on-premise deployment to meet isolation requirements. Define egress/ingress rules for SMTP, webhooks, and REST APIs with clear firewall and proxy policies.

Detail containment, forensics, and notifications using immutable logs from the parsing pipeline. Include contact trees, evidence preservation steps, and regulator reporting timelines.

Reject plaintext SMTP and require modern cipher suites for inbound messages and API calls. Monitor for downgrade attempts and log negotiated protocols.

Record DKIM pass/fail and DMARC policy disposition in the parsed JSON to inform routing and quarantine decisions. Treat failed authenticity as higher-risk input when PHI is present.

Decrypt encrypted clinical mail using keys stored in an HSM and verify signatures to ensure message integrity. Surface signer identity and verification status in structured fields.

Protect JSON deliveries by enforcing client and server certificates and limiting destination IPs. Rotate certificates regularly and alert on CN/SAN mismatches.

Sign outbound JSON with per-tenant secrets and verify on receipt to prevent tampering. Rotate shared secrets and store key IDs with each delivery for traceability.

Issue ingest-only or read-only tokens and rotate them on a defined cadence with immediate revocation capability. Monitor for anomalous token usage patterns.

Parse multipart/mixed, multipart/alternative, and multipart/related with robust boundary detection and recursion limits. Reject malformed inputs that exceed configured depth.

Normalize text to UTF-8 while preserving original charsets and encodings in metadata. This prevents data loss in clinical notes and ensures consistent downstream processing.

Prefer text/plain for clinical systems that cannot render HTML, with HTML fallback when configured. Record the chosen variant and the reason for deterministic replay.

Parse Message-ID, In-Reply-To, References, Date (with timezone), and Return-Path into explicit JSON fields. Use these to deduplicate and to thread message chains in case management.

Decode winmail.dat (TNEF), resolve Content-ID inline images, and support clinical types like application/dicom and HL7 or CDA content. Preserve accurate content-type mappings for handlers.

Set maximum message size, per-part size, and number of parts to prevent resource exhaustion. Quarantine or reject inputs that exceed thresholds and surface reasons in metadata.

Identify bounces and disposition notifications to avoid misclassifying them as patient messages. Emit structured fields indicating non-clinical status and route to operations queues.

Run malware scanning and dynamic analysis on attachments before JSON delivery or downstream storage. Quarantine positives and include scan logs in audit records.

Allow formats commonly used in healthcare such as PDF, TIFF, DICOM, HL7, and CDA while blocking executables and scripts. Validate by magic bytes, not only file extensions.

Generate safe-rendered PDFs from Office files and remove macros or embedded scripts. Deliver both the sanitized version and a pointer to the original in quarantine when policy allows.

Detect identifiers like MRNs, DOBs, and phone numbers and replace them with irreversible tokens prior to non-clinical routing. Store salted hashes for correlation without exposing raw values.

Pull StudyInstanceUID, SeriesInstanceUID, and PatientID into JSON while hashing pixel data to verify integrity. Record cryptographic digests for legal defensibility.

Convert scanned faxes or photos to text to improve PHI detection and workflow automation. Restrict OCR to approved engines and avoid exporting recognized text to non-clinical endpoints by default.

Transform extracted fields into FHIR resources (for example, DocumentReference with Binary) or HL7 segments for downstream EHR ingestion. Validate against profiles and consent constraints.

Create a deduplication key from Message-ID plus a body or attachment hash to avoid duplicate orders or documents. Persist the key and reject replays with clear telemetry.

Use the envelope recipient or tagged aliases to direct messages to facility-specific queues or tenants. Place routing metadata in JSON for transparent audit and troubleshooting.

Configure exponential backoff, jitter, and circuit breakers for webhooks, then expose a REST polling endpoint for prolonged outages. Mark deliveries with attempt counters and final status.

Convert to UTF-8 and, where clinical systems require, strip or sanitize HTML to produce plaintext. Record both original and normalized variants for traceability.

Attach a unique trace ID to each webhook or REST response and store status codes and bodies for audits. Link trace IDs back to message hashes and Message-ID for full lineage.

Prohibit real PHI in staging and test environments and use realistic, de-identified clinical emails for validation. Automate checks to prevent PHI uploads to non-prod buckets.

Maintain sample emails with nested multiparts, S/MIME, DICOM, TNEF, large attachments, and malformed boundaries. Run them in CI to prevent parser regressions.

Record access events, delivery attempts, and key fields such as Message-ID and attachment hashes to WORM or tamper-evident storage. Index logs for rapid eDiscovery and incident forensics.

Track inbound volume, parse failures, quarantines, malware hits, webhook latency, and retry counts. Route alerts to on-call with runbooks tied to each metric.

Store encrypted originals for legal hold and shorter-lived normalized JSON for operations, with explicit purge jobs. Tag artifacts by tenant and retention class for automated management.

Rotate SMTP credentials, API tokens, and webhook secrets on a defined schedule and review role assignments. Document approvals and revoke unused accounts promptly.