TLS Profiler

The TLS Profiler class provided in this library can be used to compare the configuration of a TLS server to the Mozilla TLS configuration recommendations.

The Mozilla TLS recommendations are three profiles (old, intermediate, modern) containing values for the following properties:

• TLS 1.3 cipher suites
• TLS 1.0 - 1.2 cipher suites
• Protocol versions
• Certificate types
• TLS curves for the key exchange
• DH parameter size for the key exchange
• HSTS max age
• Maximum certificate lifespan
• cipher preference (client or server choose)

TLS Profiler uses the sslyze library under the hood. This library retrieves a wide range of information about a TLS server remotely. For example, sslyze can retrieve the list of supported TLS versions. sslyze does not, however, rate the results (like Qualy's SSLLabs test does) or provide information whether the server fulfills certain criteria.

TLS Profiler is initialized with a domain (host) name and a target profile name (old, intermediate, or modern). When the run() method is called, it returns a TLS Profiler Result with the following attributes:

• validation_errors: A list of strings describing errors that occured while validating the certificate.
• certificate_warnings: A list of strings describing warnings concerning the certificate.
• profile_errors: A list of strings describing deviations from the target Mozilla profile.
• vulnerability_errors: Further vulnerabilities (like Heartbleet) that can be detected by sslyze.
• validated: Boolean indicating whether the certificate is valid.
• profile_matched: Boolean indicating whether the target profile's requirements are fulfilled.
• vulnerable: Boolean indicating whether any vulnerabilities were discovered.
• all_ok: Boolean indicating whether the certificate is valid, the profile was matched, no certificate warnings were issued and no vulnerabilities were detected.

Limitations:

1. Currently, if a server has multiple certificates only one certificate will be recognized. This is a limitation of the sslyze library (see issue #326).

Usage

To use the TLS Profiler you currently need the tls_profiler branch of the following forks: sslyze and nassl.

API usage

Basic usage of the TLS Profiler:

from tlsprofiler import TLSProfiler, PROFILE

profiler = TLSProfiler("www.example.com")
profiler.scan_server()
tls_profiler_result = profiler.compare_to_profile(PROFILE.MODERN)

Command-line usage

Help text for the command-line interface:

usage: run.py [-h] [-c CA_FILE] [-w CERT_EXPIRE_WARNING] domain [profile]

Scans the TLS settings of a server and compares them with a Mozilla TLS profile.

positional arguments:
  domain                Domain name of the server to be scanned
  profile               The Mozilla TLS profile to scan for [old|intermediate|modern]. If no profile is specified, 
                        the server's TLS settings will be compared to all profiles.

optional arguments:
  -h, --help            show this help message and exit
  -c CA_FILE, --ca-file CA_FILE
                        Path to a trusted custom root certificates in PEM format
  -w CERT_EXPIRE_WARNING, --cert-expire-warning CERT_EXPIRE_WARNING
                        A warning is issued if the certificate expires in less days than specified (default 15 days)

Example usage: python3 run.py www.example.com intermediate

To make the usage easier just build a docker container with the Dockerfile in the root directory of this repository. You have to use the following commands:

• docker build -t tlsprofiler .
• docker run tlsprofiler www.example.com intermediate

Tests

To run all tests the script ./tests/run_tests.sh from the root directory of this repository. You can call it with the argument --no-cache to rebuild the test environment from scratch.