CVE Lookup Module

Overview

The CVE Lookup module (modules/cve_lookup.py) queries public CVE databases to identify known vulnerabilities in discovered services. It provides CVSS scoring, exploit availability checking, and risk assessment.

CVELookup Class

Defined at cve_lookup.py:13, this class handles all CVE database interactions.

Initialization

cve_lookup.py:14-18

class CVELookup:
    def __init__(self):
        """Initialize CVE lookup module"""
        self.cve_data = []
        self.api_url = "https://cve.circl.lu/api"
        self.nvd_api = "https://services.nvd.nist.gov/rest/json/cves/2.0"

CVE Data Sources:

CVE CIRCL API (primary): Fast, no authentication required
NVD API (fallback): National Vulnerability Database with detailed metrics

Key Methods

search_cve_by_product()

Searches CVE databases for vulnerabilities affecting a specific product and version.

cve_lookup.py:20-64

def search_cve_by_product(self, product, version=""):
    """Search for CVEs by product name and version"""
    # Clean product name
    product_clean = product.lower().strip()
    product_clean = re.sub(r'[^\w\s-]', '', product_clean)
    
    # Query CVE CIRCL API
    search_url = f"{self.api_url}/search/{product_clean}"
    response = requests.get(search_url, timeout=10)
    
    if response.status_code == 200:
        data = response.json()
        
        # Limit to top 10 most relevant results
        for cve_entry in data[:10]:
            cve_info = self.parse_cve_entry(cve_entry)
            
            # Filter by version if specified
            if version and self.version_matches(cve_entry, version):
                cves.append(cve_info)
            else:
                cves.append(cve_info)
    
    return cves

string

required

Product name (e.g., “apache”, “openssh”, “mysql”)

string

Product version for filtering results (e.g., “2.4.41”)

parse_cve_entry()

Extracts and normalizes CVE information from API responses.

cve_lookup.py:66-111

def parse_cve_entry(self, cve_entry):
    """Parse CVE entry and extract relevant information"""
    cve_id = cve_entry.get('id', 'Unknown')
    summary = cve_entry.get('summary', 'No description available')
    
    # Get CVSS score
    cvss_score = 0.0
    if 'cvss' in cve_entry:
        cvss_score = float(cve_entry.get('cvss', 0.0))
    elif 'impact' in cve_entry:
        if 'baseMetricV3' in cve_entry['impact']:
            cvss_score = float(cve_entry['impact']['baseMetricV3']['cvssV3']['baseScore'])
        elif 'baseMetricV2' in cve_entry['impact']:
            cvss_score = float(cve_entry['impact']['baseMetricV2']['cvssV2']['baseScore'])
    
    # Determine risk level
    risk_level = self.calculate_risk_level(cvss_score)
    
    # Check exploit availability
    exploitable = self.check_exploit_availability(cve_id, cve_entry)
    
    return {
        'cve_id': cve_id,
        'description': summary[:500],
        'cvss_score': cvss_score,
        'risk_level': risk_level,
        'published_date': published,
        'exploitable': exploitable,
        'references': cve_entry.get('references', [])[:3]
    }

CVSS Score Interpretation

calculate_risk_level()

Maps CVSS scores to risk severity levels.

cve_lookup.py:113-124

def calculate_risk_level(self, cvss_score):
    """Calculate risk level based on CVSS score"""
    if cvss_score >= 9.0:
        return "CRITICAL"
    elif cvss_score >= 7.0:
        return "HIGH"
    elif cvss_score >= 4.0:
        return "MEDIUM"
    elif cvss_score > 0.0:
        return "LOW"
    else:
        return "UNKNOWN"

CVSS v3 Severity Ratings:

Score Range	Severity	Color	Priority
9.0 - 10.0	CRITICAL	Red	Immediate action required
7.0 - 8.9	HIGH	Orange	Fix within 30 days
4.0 - 6.9	MEDIUM	Yellow	Fix within 90 days
0.1 - 3.9	LOW	Blue	Fix when convenient
0.0	INFORMATIONAL	Gray	No action needed

Exploit Detection

check_exploit_availability()

Determines if public exploits are available for a CVE.

cve_lookup.py:126-142

def check_exploit_availability(self, cve_id, cve_entry):
    """Check if exploit is publicly available"""
    # Check in CVE data
    if 'exploit-db' in str(cve_entry).lower():
        return True
    
    if 'metasploit' in str(cve_entry).lower():
        return True
    
    # Check references
    if 'references' in cve_entry:
        for ref in cve_entry['references']:
            ref_str = str(ref).lower()
            if any(keyword in ref_str for keyword in 
                ['exploit', 'poc', 'metasploit', 'exploit-db']):
                return True
    
    return False

Exploit Sources Checked:

Exploit-DB
Metasploit Framework
Proof-of-Concept (PoC) repositories
Security advisories with exploit code

Service CVE Lookup

lookup_services()

Looks up CVEs for all discovered services from port scan.

cve_lookup.py:160-185

def lookup_services(self, services):
    """Look up CVEs for list of services"""
    all_cves = []
    
    for service in services:
        port = service.get('port')
        service_name = service.get('service', '')
        version = service.get('version', '')
        
        # Skip generic services
        if not service_name or service_name in ['unknown', 'tcpwrapped']:
            continue
        
        # Search for CVEs
        cves = self.search_cve_by_product(service_name, version)
        
        # Attach port information
        for cve in cves:
            cve['port'] = port
            cve['service'] = service_name
            cve['version'] = version
            all_cves.append(cve)
    
    return all_cves

The module automatically skips generic services like “unknown” or “tcpwrapped” to reduce false positives.

Usage Example

from modules.cve_lookup import CVELookup
from modules.scanner import Scanner

# Get services from scan
scanner = Scanner("192.168.1.100")
scan_results = scanner.run_full_scan()

# Look up CVEs
cve_lookup = CVELookup()
cves = cve_lookup.lookup_services(scan_results['services'])

# Display results
for cve in cves:
    print(f"Port {cve['port']}: {cve['cve_id']}")
    print(f"  Service: {cve['service']} {cve['version']}")
    print(f"  CVSS: {cve['cvss_score']} ({cve['risk_level']})")
    print(f"  Exploitable: {cve['exploitable']}")
    print(f"  Description: {cve['description']}")

Output Format

[
  {
    "port": 22,
    "service": "ssh",
    "version": "OpenSSH 7.4",
    "cve_id": "CVE-2018-15473",
    "description": "OpenSSH through 7.7 allows remote attackers to enumerate users...",
    "cvss_score": 5.3,
    "risk_level": "MEDIUM",
    "published_date": "2018-08-17",
    "exploitable": true,
    "references": [
      "https://github.com/Rhynorater/CVE-2018-15473-Exploit",
      "https://nvd.nist.gov/vuln/detail/CVE-2018-15473"
    ]
  }
]

Rate Limiting

The module implements rate limiting to respect API usage policies:

cve_lookup.py:56-57

# Rate limiting between requests
time.sleep(1)  # 1 second delay per request

Excessive API requests may result in temporary IP blocking. The built-in rate limiting prevents this.

Configuration

CVE lookup settings in config.json:

config.json

{
  "cve_lookup": {
    "enabled": true,
    "api_url": "https://cve.circl.lu/api",
    "nvd_api_url": "https://services.nvd.nist.gov/rest/json/cves/2.0",
    "max_results_per_service": 10,
    "cache_results": true
  }
}

boolean

default:true

Enable/disable CVE lookup during scans

number

default:10

Maximum CVEs to return per service (prevents overwhelming results)

boolean

default:true

Cache CVE data to reduce API calls

Error Handling

API Timeout

Requests timeout after 10 seconds. Returns empty results and continues scanning.

response = requests.get(search_url, timeout=10)

No Results Found

Returns empty list if no CVEs match the service/version.Common causes:

Service version too new (no CVEs yet)
Product name not in CVE database
Version string parsing failed

Network Error

Catches connection errors and continues scan.

except requests.exceptions.RequestException as e:
    print(f"[!] CVE lookup failed: {e}")
    return []

Risk Engine

How CVE data is used in risk scoring

Exploit Engine

Matching CVEs to available exploits

PDF Reports

CVE information in generated reports

Configuration

CVE lookup settings

CLI Commands

Modules

Output & Reports

Overview

CVELookup Class

Initialization

Key Methods

search_cve_by_product()

parse_cve_entry()

CVSS Score Interpretation

calculate_risk_level()

Exploit Detection

check_exploit_availability()

Service CVE Lookup

lookup_services()

Usage Example

Output Format

Rate Limiting

Configuration

Error Handling

Risk Engine

Exploit Engine

PDF Reports

Configuration

​Overview

​CVELookup Class

​Initialization

​Key Methods

​search_cve_by_product()

​parse_cve_entry()

​CVSS Score Interpretation

​calculate_risk_level()

​Exploit Detection

​check_exploit_availability()

​Service CVE Lookup

​lookup_services()

​Usage Example

​Output Format

​Rate Limiting

​Configuration

​Error Handling

​Related Documentation

Risk Engine

Exploit Engine

PDF Reports

Configuration

Overview

CVELookup Class

Initialization

Key Methods

search_cve_by_product()

parse_cve_entry()

CVSS Score Interpretation

calculate_risk_level()

Exploit Detection

check_exploit_availability()

Service CVE Lookup

lookup_services()

Usage Example

Output Format

Rate Limiting

Configuration

Error Handling

Related Documentation