Enriching IOCs with Threat Intel Sources
When to Use
- You have atomic indicators and need context: reputation, related infrastructure, first/last
seen, and known associations.
- You are scoring indicator confidence before acting or reporting.
- You must plan lookups without leaking your investigation to the adversary.
Do not use active interaction (visiting a C2 URL, resolving a live domain from your own
network) for enrichment — use passive sources to avoid tipping off the adversary.
Prerequisites
- Defanged indicators (from the defanging skill) and access to enrichment sources/APIs.
- Awareness of each source's operational-security implications.
Safety & Handling
- Prefer passive sources (passive DNS, sample DBs, reputation feeds) over active probing.
- Never submit a customer/internal sample to a public sandbox without authorization — it becomes
publicly retrievable and can expose sensitive data.
Workflow
Step 1: Group indicators by type
Separate hashes, domains, IPs, and URLs; each maps to different enrichment sources.
Step 2: Plan the right lookups
Map each type to passive sources: hashes → sample/AV databases; domains → passive DNS, WHOIS,
reputation; IPs → ASN/geo, passive DNS, reputation; URLs → URL reputation/sandbox history.
python scripts/analyst.py plan iocs.json
Step 3: Score confidence
Combine source agreement, age, and prevalence into a confidence score; a single hit on one feed
is weaker than corroboration across independent sources.
Step 4: Annotate and pivot
Attach context (first seen, related infrastructure, family) and pivot on strong links (shared
registrant, hosting, certificate) to expand the picture.
Step 5: Record provenance
Note which source provided each piece of context and when, so the enrichment is auditable and
re-checkable.
Validation
- Each indicator is routed to type-appropriate, passive sources.
- Confidence reflects corroboration across independent sources, not a single feed.
- Every enrichment carries source and timestamp provenance.
Pitfalls
- Actively resolving/visiting live infrastructure and alerting the adversary.
- Uploading sensitive samples to public services, leaking data.
- Treating one feed's verdict as ground truth without corroboration.
References