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SSLyze

SSLyze is a fast and full-featured SSL/TLS scanner that analyzes server configurations by connecting to them. It helps identify misconfigurations affecting SSL servers.

Description

SSLyze is a Python tool designed to be fast and comprehensive for analyzing the SSL configuration of servers. It connects directly to the target server to perform various checks, aiding organizations and testers in identifying issues like compression support that could enable attacks such as CRIME, certificate validity problems, and other TLS misconfigurations.

Use cases include auditing SSL/TLS deployments for security weaknesses, verifying certificate trust using Mozilla's CA store, testing session resumption and renegotiation, and scanning cipher suites. The tool supports multiple connectivity options like proxies and StartTLS protocols for broader applicability.

It provides detailed scan results on aspects like compression support, certificate validation, and plugin-based analysis for OpenSSL cipher suites and elliptic curves.

How It Works

SSLyze connects to the target server over SSL/TLS and runs registered plugins such as PluginCompression, PluginCertInfo, PluginSessionResumption, PluginSessionRenegotiation, and PluginOpenSSLCipherSuites. It checks host availability, performs scans like certificate validation against Mozilla's CA store or custom CAs, tests for TLS compression (CRIME vulnerability), session handling, and supports custom TLS configurations via JSON files following Mozilla's format. Results are generated from direct server interactions and can be output in JSON format matching the Python API.

Installation

bash
sudo apt install sslyze

Flags

--regularLaunch a regular scan type against the target host
--certinfoRetrieve and analyze a server's certificate(s) to verify its validity
--certinfo_ca_file CERTINFO_CA_FILEPath to a file containing root certificates in PEM format that will be used to verify the validity of the server's certificate
--compressionTest a server for TLS compression support, which can be leveraged to perform a CRIME attack
--json_out JSON_FILEWrite the scan results as a JSON document to the file JSON_FILE
--slow_connectionGreatly reduce the number of concurrent connections initiated by SSLyze for slow or unreliable connections
--https_tunnel PROXY_SETTINGSTunnel all traffic to the target server(s) through an HTTPS proxy
--update_trust_storesUpdate the default trust stores used by SSLyze from https://github.com/nabla-c0d3/trust_stores_observatory

Examples

Launch a regular scan type against the target host www.example.com
sslyze --regular www.example.com
Retrieve and analyze the server's certificate(s) to verify its validity
sslyze --certinfo www.example.com
Test the server for TLS compression support vulnerable to CRIME attack
sslyze --compression www.example.com
Perform a scan and write results as JSON to results.json
sslyze --json_out results.json www.example.com
Scan with reduced concurrent connections for slow or unreliable networks
sslyze --slow_connection www.example.com
Scan the target by tunneling traffic through an HTTPS proxy
sslyze --https_tunnel proxy.example.com:8080 www.example.com
Update SSLyze's default trust stores from the observatory repository
--update_trust_stores
Updated 2026-04-16kali.org ↗