Implementing mTLS for Zero Trust Services

When to Use

• When deploying or configuring implementing mtls for zero trust services capabilities in your environment
• When establishing security controls aligned to compliance requirements
• When building or improving security architecture for this domain
• When conducting security assessments that require this implementation

Prerequisites

• Familiarity with security operations concepts and tools
• Access to a test or lab environment for safe execution
• Python 3.8+ with required dependencies installed
• Appropriate authorization for any testing activities

Instructions

Generate CA certificates, issue service certificates, and configure mutual TLS verification for service-to-service authentication.

python
from cryptography import x509
from cryptography.x509.oid import NameOID
from cryptography.hazmat.primitives import hashes, serialization
from cryptography.hazmat.primitives.asymmetric import rsa
import datetime

# Generate CA key and certificate
ca_key = rsa.generate_private_key(public_exponent=65537, key_size=4096)
ca_cert = (x509.CertificateBuilder()
    .subject_name(x509.Name([x509.NameAttribute(NameOID.COMMON_NAME, "Internal CA")]))
    .issuer_name(x509.Name([x509.NameAttribute(NameOID.COMMON_NAME, "Internal CA")]))
    .public_key(ca_key.public_key())
    .serial_number(x509.random_serial_number())
    .not_valid_before(datetime.datetime.utcnow())
    .not_valid_after(datetime.datetime.utcnow() + datetime.timedelta(days=3650))
    .add_extension(x509.BasicConstraints(ca=True, path_length=None), critical=True)
    .sign(ca_key, hashes.SHA256()))

Examples

python
import ssl
context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
context.load_cert_chain("client.pem", "client-key.pem")
context.load_verify_locations("ca.pem")
context.verify_mode = ssl.CERT_REQUIRED