Python for Cybersecurity (Intermediate) Building your own Automated Vulnerability Scanner (Tutorial)
Learn how to build an automated vulnerability scanner in Python that detects insecure configurations in seconds. In this tutorial, we break down the full script step-by-step, explain the logic behind pattern matching, and show you how to reliably scan config files for common security risks.
Whether you’re studying cybersecurity, building tools for your homelab, or preparing for a SOC/analyst role, this project is perfect for learning automation, file parsing, and real-world security workflow design. Enjoy.
Below will be the code for those who don't want to sit and watch a 20-minute tutorial when they can use AI tools to assist in explaining as well.
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#UseResponsibly
import os
def create_sample_config():
"""Creates a sample config file with insecure settings."""
config = """DB_PASSWORD=admin123
DB_USER=root
API_KEY=sk-1234567890abcdef
DEBUG_MODE=true
SSL_ENABLED=false
ADMIN_PASSWORD=password
FIREWALL_DISABLED=yes"""
with open("server_config.txt", 'w') as f:
f.write(config)
print("[+] Created server_config.txt")
return "server_config.txt"
def get_patterns():
"""Returns vulnerability patterns to search for."""
return {
"weak_password": {
"search": ["password=admin", "password=password"],
"severity": "HIGH",
"message": "Weak password detected - easy to guess"
},
"exposed_secrets": {
"search": ["API_KEY=", "SECRET_TOKEN="],
"severity": "CRITICAL",
"message": "Secret found in config file - should use environment variables"
},
"insecure_settings": {
"search": ["SSL_ENABLED=false", "FIREWALL_DISABLED=yes", "DEBUG_MODE=true"],
"severity": "HIGH",
"message": "Insecure setting detected - security feature disabled"
},
"default_credentials": {
"search": ["DB_USER=root", "ADMIN_PASSWORD"],
"severity": "HIGH",
"message": "Default credentials found - change immediately"
}
}
def scan_file(filename, patterns):
"""Scans file for vulnerabilities."""
findings = []
if not os.path.exists(filename):
print(f"[-] File '{filename}' not found!")
return findings
with open(filename, 'r') as f:
lines = f.readlines()
for line_num, line in enumerate(lines, start=1):
line_upper = line.upper().strip()
for vuln_name, vuln_info in patterns.items():
for search_term in vuln_info["search"]:
if search_term.upper() in line_upper:
findings.append({
"line": line_num,
"content": line.strip(),
"severity": vuln_info["severity"],
"message": vuln_info["message"]
})
break
return findings
def print_report(findings):
"""Prints vulnerability report."""
print("\n" + "=" * 60)
print("VULNERABILITY SCAN REPORT")
print("=" * 60)
if not findings:
print("\n[+] No vulnerabilities found!\n")
return
critical = sum(1 for f in findings if f["severity"] == "CRITICAL")
high = sum(1 for f in findings if f["severity"] == "HIGH")
print(f"\nTotal: {len(findings)} | Critical: {critical} | High: {high}\n")
for severity in ["CRITICAL", "HIGH"]:
severity_findings = [f for f in findings if f["severity"] == severity]
if severity_findings:
print(f"[!] {severity} ISSUES:")
for idx, f in enumerate(severity_findings, 1):
print(f" {idx}. Line {f['line']}: {f['content']}")
print(f" {f['message']}\n")
print("=" * 60 + "\n")
def main():
"""Main function."""
print("=" * 60)
print("AUTO VULNERABILITY SCANNER")
print("=" * 60)
filename = create_sample_config()
patterns = get_patterns()
print(f"[+] Loaded {len(patterns)} patterns")
findings = scan_file(filename, patterns)
print_report(findings)
print("Scan complete!\n")
if _name_ == "__main__":
main()