x509-parser

Simple Python (only supports Python3) utility to help parse X509 certificates. This utility will allow the parsing of X509 certificates via:

Directly from a web server.
From a text file containing the X509 certificate
From the command line.

This tool supports the ability to parse multiple X509 certificates from either a specified file, or via command line input into the tool.

Installation

Install the required modules:

pip install -r requirements.txt

Usage

For parsing a X509 certificate from a web server:

To use the default port of 443: python x509_parser.py -i <host> or python x509_parser.py --host <host>

To use a custom port: python x509_parser.py -i <host> -p <port> or python x509_parser.py --host <host> --port <port>

For parsing a X509 certificate from a text file:

python x509_parser.py -f <filename> or python x509_parser.py -file <filename>

For parsing a X509 certificate from the command line:

python x509_parser.py -d or python x509_parser.py --dump

Output

All format of the tool is produced in JSON format. By default the tool will dump the parsing of the certificates in to the standard output. There is support to have the output placed into a file instead, which can be done via the argument -o or --output followed by the filename of the file to place the output into.

Certificate Validation

You can ignore certificate validation (only applicable when obtaining a certificate from a server), by specifying the argument -v or --ignore-cert-validation.

X509 Certificate Extensions

Due to what appears to be a bug in the OpenSSL Python library (an error occurs while attempting to obtain the extensions of some certificates), there is a flag which enables to one to ignore the extension field (i.e. don't include it in the parsing of the X509 certificates). You can set this flag via the -e or --ignore-extensions arguments.

Example

swright@swright-XPS-13-9360:~/workspace/x509-parser$ python x509_parser.py -i www.google.com
{
    "certs": [
        {
            "subject": {
                "C": "US",
                "ST": "California",
                "L": "Mountain View",
                "O": "Google LLC",
                "CN": "www.google.com"
            },
            "issuer": {
                "C": "US",
                "O": "Google Trust Services",
                "CN": "Google Internet Authority G3"
            },
            "has-expired": false,
            "not-after": "2019-07-30 10:55:00",
            "not-before": "2019-05-07 11:32:17",
            "extensions": {
                "extendedKeyUsage": "TLS Web Server Authentication",
                "keyUsage": "Digital Signature",
                "subjectAltName": "DNS:www.google.com",
                "authorityInfoAccess": "CA Issuers - URI:http://pki.goog/gsr2/GTSGIAG3.crt\nOCSP - URI:http://ocsp.pki.goog/GTSGIAG3\n",
                "subjectKeyIdentifier": "82:4A:FB:FA:18:7D:37:BA:5A:41:AC:A2:BF:77:34:47:50:D7:55:FE",
                "basicConstraints": "CA:FALSE",
                "authorityKeyIdentifier": "keyid:77:C2:B8:50:9A:67:76:76:B1:2D:C2:86:D0:83:A0:7E:A6:7E:BA:4B\n",
                "certificatePolicies": "Policy: 1.3.6.1.4.1.11129.2.5.3\nPolicy: 2.23.140.1.2.2\n",
                "crlDistributionPoints": "\nFull Name:\n  URI:http://crl.pki.goog/GTSGIAG3.crl\n"
            },
            "serial-number": 20737766121738423495711577062012920074,
            "serial-number(hex)": "0xf99f2cf47e903a4abc638ae2a54a10a",
            "signature-algorithm": "sha256WithRSAEncryption",
            "version": 2,
            "pulic-key-length": 256
        }
    ]
}

P8ace/x509-parser