IOC Threat Hunt Skill

Proactively hunt for specific Indicators of Compromise (IOCs) across the environment based on threat intelligence feeds, recent incidents, or emerging threats.

Inputs

• IOC_LIST - Comma-separated list of IOC values to hunt
• IOC_TYPES - Corresponding types (e.g., "IP Address, Domain, File Hash")
• HUNTTIMEFRAMEHOURS - Lookback period (default: 96)
• (Optional) HUNTCASEID - SOAR case for tracking
• (Optional) REASONFORHUNT - Why these IOCs are being hunted

Workflow

Step 1: Parse and Validate IOCs

Parse IOCLIST and IOCTYPES into structured list. Validate IOC formats (IP regex, hash length, etc.).

Step 2: Initial IOC Match Check

secops-mcp.get_ioc_matches(hours_back=HUNT_TIMEFRAME_HOURS)

Check if any IOCs appear in integrated threat feeds.

Step 3: Iterative SIEM Search

For each IOC, construct appropriate UDM query:

IP Address:

(principal.ip = "IOC" OR target.ip = "IOC" OR network.ip = "IOC")

Domain:

(principal.hostname = "IOC" OR target.hostname = "IOC" OR network.dns.questions.name = "IOC")

File Hash:

(target.file.sha256 = "IOC" OR target.file.md5 = "IOC" OR target.file.sha1 = "IOC")

URL:

target.url = "IOC"

Execute each search:

secops-mcp.search_security_events(text=query, hours_back=HUNT_TIMEFRAME_HOURS)

Step 4: Analyze Results

For each search result:

• Identify affected hosts, users, processes
• Note event types (login, network connection, file execution)
• Assess if activity is suspicious or expected

Step 5: Enrich Hits

If hits found for an IOC:

Use /enrich-ioc for the IOC itself.

For involved entities (hosts, users):

secops-mcp.lookup_entity(entity_value=ENTITY)

Step 6: Document Hunt

Use /document-in-case (if HUNTCASEID provided):

IOC Hunt Summary:
- IOCs Hunted: [list]
- Timeframe: [hours]
- Queries Used: [list with results summary]
- IOCs with Hits: [list with details]
- IOCs with No Hits: [list - confirms environment is clean]
- Enrichment: [for hits]
- Recommendations: [next steps]

Step 7: Escalate or Conclude

Confirmed malicious activity: → Create/update incident case → Trigger appropriate response runbook

No significant findings: → Document hunt completion → Note clean IOCs for future reference

Output Summary Template

# IOC Hunt Results

**Hunt Date:** [timestamp]
**Timeframe:** Last [X] hours
**Reason:** [REASON_FOR_HUNT]

## IOCs Searched
| IOC | Type | Result | Notes |
|-----|------|--------|-------|
| 198.51.100.10 | IP | NO HITS | Clean |
| evil.com | Domain | 3 HITS | DNS lookups from HOST1 |

## Hits Analysis
[Details for each IOC with hits]

## Recommendations
[Actions to take]

Required Outputs

After completing this skill, you MUST report these outputs:

Critical Requirements

• Search ALL provided IOCs (don't skip any)
• Use correct timeframe (not 1 hour instead of 72)
• Document negative results (confirms environment is clean)
• Don't declare "clean" if there were obvious hits