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Last active April 14, 2024 07:16
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Python script to check on SSL certificates
# -*- encoding: utf-8 -*-
# requires a recent enough python with idna support in socket
# pyopenssl, cryptography and idna
from OpenSSL import SSL
from cryptography import x509
from cryptography.x509.oid import NameOID
import idna
from socket import socket
from collections import namedtuple
HostInfo = namedtuple(field_names='cert hostname peername', typename='HostInfo')
('', 443),
('', 443),
('', 443),
('', 443),
('faß.de', 443),
('самодеј.мкд', 443),
def verify_cert(cert, hostname):
# verify notAfter/notBefore, CA trusted, servername/sni/hostname
# service_identity.pyopenssl.verify_hostname(client_ssl, hostname)
# issuer
def get_certificate(hostname, port):
hostname_idna = idna.encode(hostname)
sock = socket()
sock.connect((hostname, port))
peername = sock.getpeername()
ctx = SSL.Context(SSL.SSLv23_METHOD) # most compatible
ctx.check_hostname = False
ctx.verify_mode = SSL.VERIFY_NONE
sock_ssl = SSL.Connection(ctx, sock)
cert = sock_ssl.get_peer_certificate()
crypto_cert = cert.to_cryptography()
return HostInfo(cert=crypto_cert, peername=peername, hostname=hostname)
def get_alt_names(cert):
ext = cert.extensions.get_extension_for_class(x509.SubjectAlternativeName)
return ext.value.get_values_for_type(x509.DNSName)
except x509.ExtensionNotFound:
return None
def get_common_name(cert):
names = cert.subject.get_attributes_for_oid(NameOID.COMMON_NAME)
return names[0].value
except x509.ExtensionNotFound:
return None
def get_issuer(cert):
names = cert.issuer.get_attributes_for_oid(NameOID.COMMON_NAME)
return names[0].value
except x509.ExtensionNotFound:
return None
def print_basic_info(hostinfo):
s = '''» {hostname} « … {peername}
\tcommonName: {commonname}
\tSAN: {SAN}
\tissuer: {issuer}
\tnotBefore: {notbefore}
\tnotAfter: {notafter}
def check_it_out(hostname, port):
hostinfo = get_certificate(hostname, port)
import concurrent.futures
if __name__ == '__main__':
with concurrent.futures.ThreadPoolExecutor(max_workers=4) as e:
for hostinfo in x: get_certificate(x[0], x[1]), HOSTS):
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alfonsrv commented Mar 13, 2021

Insanely dope script. namedtuple just blew my mind.
Any idea on how to verify the chain?

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tomtrkd commented Jun 23, 2021

I am having problems with the verify_cert option is this working correctly and is there a way to check a self signed certificate?

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suharevA commented Dec 4, 2021

How to add the output of the organization that issued the certificate to the script. For example
(O) Let's Encrypt

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suharevA commented Dec 4, 2021

Everything. Figured it out
names_o = cert.issuer.get_attributes_for_oid(NameOID.ORGANIZATION_NAME)

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when I get a list of sites and one of them does not have a TLS certificate configured, it generates an error:
sock.connect((hostname, port))
BlockingIOError: [Errno 11] Resource temporarily unavailable

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Would it be possible to convert the cert to a byte string or an instance of asn1crypto.x509.Certificate please?

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Hi, the script is useful, but it's possible put these values: ('', 443), ('', 443), ('', 443), ('', 443), ('faß.de', 443), ('самодеј.мкд', 443), inside a text file? I mean exist an elegant way to read lines of file into list?

you can change HOSTS into this:

HOSTS = []

for line in hosts_file:
host, port = line.strip().split(':')
HOSTS.append((host, int(port)))

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I really appreciate that you took the time to share this with the world... super useful !!! Thank you.

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leejhn commented May 11, 2023

Thank you so much for being so helpful.

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cert.has_expired() doesn't work for this version. Is there a workaround?
'cryptography.hazmat.bindings._rust.x509.Certificat' object has no attribute 'has_expired'

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gdamjan commented Jul 26, 2023

cert.has_expired() doesn't work for this version.

and what is "this" version !?!

Is there a workaround?

install "another" version?!

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