Extract common name from TLS certificate via URLs

extract_cn.py

import ssl
import socket
from urllib.parse import urlparse
from cryptography import x509
from cryptography.hazmat.backends import default_backend

def get_certificate_common_name(url, timeout=3):
    # Parse the URL to get the hostname
    parsed_url = urlparse(url)
    hostname = parsed_url.hostname
    
    # Connect to the host and get the SSL certificate
    context = ssl.create_default_context()
    context.check_hostname = False
    context.verify_mode = ssl.CERT_NONE
    with socket.create_connection((hostname, 443), timeout=timeout) as sock:
        with context.wrap_socket(sock, server_hostname=hostname) as ssock:
            cert_bin = ssock.getpeercert(binary_form=True)
    
    # Parse the certificate and extract the common name (CN)
    cert = x509.load_der_x509_certificate(cert_bin, default_backend())
    common_name = cert.subject.get_attributes_for_oid(x509.NameOID.COMMON_NAME)[0].value
    
    return common_name

def print_certificate_common_name_for_urls(urls):
    for url in urls:
        try:
            common_name = get_certificate_common_name(url)
            print(f"The common name (CN) of the SSL certificate for {url} is: {common_name}")
        except Exception as e:
            print(f"Error processing {url}: {e}")

def main():
    urls = [
        "https://test1.com",
        "https://test2.com",
    ]
    print_certificate_common_name_for_urls(urls)

if __name__ == "__main__":
    main()