Triaging Vulnerabilities With Ssvc FrameworkSAFE

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The instruction file, verbatim from the audited commit — this is the text the model reads, and the surface the audit's instruction layer examines. Quoted here so you can judge it without cloning anything.

---
name: triaging-vulnerabilities-with-ssvc-framework
description: Triages and prioritizes vulnerabilities with CISA's Stakeholder-Specific
  Vulnerability Categorization (SSVC) decision tree, weighing exploitation status
  (via the CISA KEV catalog and FIRST EPSS API), technical impact, automatability,
  and mission prevalence to output Track/Track*/Attend/Act decisions. Use when
  prioritizing vulnerability scan results (OpenVAS, Nessus, Qualys) for remediation
  planning beyond raw CVSS scores.
domain: cybersecurity
subdomain: vulnerability-management
tags:
- ssvc
- vulnerability-triage
- cisa
- vulnerability-prioritization
- decision-tree
- cvss
- remediation
- risk-management
version: '1.0'
author: mahipal
license: Apache-2.0
nist_csf:
- ID.RA-01
- ID.RA-02
- ID.IM-02
- ID.RA-06
mitre_attack:
- T1190
- T1203
- T1068
---

# Triaging Vulnerabilities with SSVC Framework

## Overview

The Stakeholder-Specific Vulnerability Categorization (SSVC) framework, developed by Carnegie Mellon University's Software Engineering Institute (SEI) in collaboration with CISA, provides a structured decision-tree methodology for vulnerability prioritization. Unlike CVSS alone, SSVC accounts for exploitation status, technical impact, automatability, mission prevalence, and public well-being impact to produce one of four actionable outcomes: **Track**, **Track***, **Attend**, or **Act**.


## When to Use

- When managing security operations that require triaging vulnerabilities with ssvc framework
- When improving security program maturity and operational processes
- When establishing standardized procedures for security team workflows
- When integrating threat intelligence or vulnerability data into operations

## Prerequisites

- Python 3.9+ with `requests`, `pandas`, and `jinja2` libraries
- Access to CISA KEV catalog API and EPSS API from FIRST
- NVD API key (optional, for higher rate limits)
- Vulnerability scan results from tools like OpenVAS, Nessus, or Qualys

## SSVC Decision Points

### 1. Exploitation Status
Assess current exploitation activity:
- **None** - No evidence of active exploitation
- **PoC** - Proof-of-concept exists publicly
- **Active** - Active exploitation observed in the wild (check CISA KEV)

```bash
# Check if a CVE is in CISA Known Exploited Vulnerabilities catalog
curl -s "https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json" | \
  python3 -c "import sys,json; data=json.load(sys.stdin); cves=[v['cveID'] for v in data['vulnerabilities']]; print('Active' if 'CVE-2024-3400' in cves else 'Check PoC/None')"
```

### 2. Technical Impact
Determine scope of compromise if exploited:
- **Partial** - Limited to a subset of system functionality or data
- **Total** - Full control of the affected system, complete data access

### 3. Automatability
Evaluate if exploitation can be automated at scale:
- **No** - Requires manual, targeted exploitation per victim
- **Yes** - Can be scripted or worm-like propagation is possible

### 4. Mission Prevalence
How widespread is the affected product in your environment:
- **Minimal** - Limited deployment, non-critical systems
- **Support** - Supports mission-critical functions indirectly
- **Essential** - Directly enables core mission capabilities

### 5. Public Well-Being Impact
Potential consequences for physical safety and public welfare:
- **Minimal** - Negligible impact on safety or public services
- **Material** - Noticeable degradation of public services
- **Irreversible** - Loss of life, major property damage, or critical infrastructure failure

## SSVC Decision Outcomes

| Outcome | Action Required | SLA |
|---------|----------------|-----|
| **Track** | Monitor, remediate in normal patch cycle | 90 days |
| **Track*** | Monitor closely, prioritize in next patch window | 60 days |
| **Attend** | Escalate to senior management, accelerate remediation | 14 days |
| **Act** | Apply mitigations immediately, executive-level awareness | 48 hours |

## Workflow

### Step 1: Ingest Vulnerability Data
```python
import requests
import json

# Fetch CISA KEV catalog
kev_url = "https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json"
kev_data = requests.get(kev_url).json()
kev_cves = {v['cveID'] for v in kev_data['vulnerabilities']}

# Fetch EPSS scores for context
epss_url = "https://api.first.org/data/v1/epss"
epss_response = requests.get(epss_url, params={"cve": "CVE-2024-3400"}).json()
```

### Step 2: Evaluate Each Decision Point
```python
def evaluate_exploitation(cve_id, kev_set):
    """Determine exploitation status from CISA KEV and EPSS data."""
    if cve_id in kev_set:
        return "active"
    epss = requests.get(
        "https://api.first.org/data/v1/epss",
        params={"cve": cve_id}
    ).json()
    if epss.get("data"):
        score = float(epss["data"][0].get("epss", 0))
        if score > 0.5:
            return "poc"
    return "none"

def evaluate_technical_impact(cvss_vector):
    """Parse CVSS vector for scope and impact metrics."""
    if "S:C" in cvss_vector or "C:H/I:H/A:H" in cvss_vector:
        return "total"
    return "partial"

def evaluate_automatability(cvss_vector, cve_description):
    """Check if attack vector is network-based with low complexity."""
    if "AV:N" in cvss_vector and "AC:L" in cvss_vector and "UI:N" in cvss_vector:
        return "yes"
    return "no"
```

### Step 3: Apply SSVC Decision Tree
```python
def ssvc_decision(exploitation, tech_impact, automatability, mission_prevalence, public_wellbeing):
    """CISA SSVC decision tree implementation."""
    if exploitation == "active":
        if tech_impact == "total" or automatability == "yes":
            return "Act"
        if mission_prevalence in ("essential", "support"):
            return "Act"
        return "Attend"
    if exploitation == "poc":
        if automatability == "yes" and tech_impact == "total":
            return "Attend"
        if mission_prevalence == "essential":
  

SAFEgrade B · trust 89/100 Nothing in the source contradicts what it says it does. Grade A is reserved for packages that have also passed the behavioural sandbox.

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declared (5 observation(s))

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pinned

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Gates applied: no_behavioural_pass.