cert-hero 0.1.0

Python Stand-alone Library to Download SSL Certificate for Any Host™

Cert Hero

Python Stand-alone Library to Download SSL Certificate for Any Host™

• Free software: MIT license

• Documentation: https://cert-hero.readthedocs.io.

Rationale

The builtin Python module ssl can be used to retrieve a certificate from a server via getpeercert, but it’ll work only if the certificate of interest can be successfully verified (source).

If, for any reason, verification fails, like, for example, with expired or a self-signed certificate, we’ll get ssl.SSLCertVerificationError instead of the requested info.

We can work around this by asking for the certificate in the binary form:

getpeercert(binary_form=True)

But now we have to convert it, and thus we can use a third party asn1crypto module, instead of the (bulkier) cryptography module.

Usage

Retrieve the certificate for host google.com:

import json
import cert_hero

cert = cert_hero.cert_please('google.com')

print('Cert is Valid Till:', cert.not_after_date.isoformat())
print(f'Cert Details:', json.dumps(cert, indent=2), sep='\n')

Output (Sample):

Cert is Valid Till: 2023-10-28
Cert Details:
{
  "Serial": "753DD6FF20CB1B4510CB4C1EA27DA2EB",
  "Subject Name": {
    "Common Name": "*.google.com"
  },
  "Issuer Name": {
    "Country": "US",
    "State/Province": "California",
    "Organization": "Zscaler Inc.",
    "Organization Unit": "Zscaler Inc.",
    "Common Name": "Zscaler Intermediate Root CA (zscalerthree.net) (t) "
  },
  "Validity": {
    "Not After": "2023-10-28",
    "Not Before": "2023-10-14"
  },
  "Wildcard": true,
  "Signature Algorithm": "SHA256WITHRSA",
  "Key Algorithm": "RSA-2048",
  "Subject Alt Names": [
    "*.google.com",
    "*.appengine.google.com",
    "youtu.be",
    "*.youtube.com",
    ...
  ],
  "Location": "https://www.google.com/",
  "Status": 301
}

Usage as a CLI

After the installation step you can use cert-hero just typing ch in your terminal window.

The ch command allows you to retrieve the SSL certificate(s) for one or more given host.

For example:

ch google.com cnn.com

You can get help about the main command using:

ch --help

Credits

This package was created with Cookiecutter and the rnag/cookiecutter-pypackage project template.

History

0.1.0 (2023-10-16)

• First release on PyPI.