Python requests SSL error - certificate verify failed

Question

This code

import requests
requests.get("https://hcaidcs.phe.org.uk/WebPages/GeneralHomePage.aspx")

is giving me this error

[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:777)

I know practically nothing about SSL, but I've tried downloading the site's certificate and pointing to that file using the verify option, but it hasn't worked. Am I missing something?

The site has a bad SSL Implementation: https://www.ssllabs.com/ssltest/analyze.html?d=hcaidcs.phe.org.uk — Klaus D., Oct 06 '17 at 11:09
Does this answer your question? [Python Requests throwing SSLError](https://stackoverflow.com/questions/10667960/python-requests-throwing-sslerror) — ggorlen, Jan 12 '23 at 22:14

score 46 · Accepted Answer · answered Oct 06 '17 at 11:40

As already pointed out in a comment: the site has a bad SSL implementation as can be seen from the SSLLabs report. The main part of this report regarding your problem is:

This server's certificate chain is incomplete. Grade capped to B.

This means that the server is not sending the full certificate chain as is needed to verify the certificate. This means you need to add the missing certificates yourself when validating. For this you need to include the PEM for the missing chain certificate C=US, O=DigiCert Inc, OU=www.digicert.com, CN=DigiCert SHA2 High Assurance Server CA and also for the root CA C=US, O=DigiCert Inc, OU=www.digicert.com, CN=DigiCert High Assurance EV Root CA info a file my_trust_store.pem and then you can call:

requests.get("https://...", verify='my_trust_store.pem')

... but I've tried downloading the site's certificate and pointing to that file using the verify option

This will not work with normal leaf certificates. Since the SSL stack of Python is based on OpenSSL and OpenSSL expects only trusted certificate authorities in the trust store (i.e. given with verify) and a server certificate is not CA certificate it will not help to add it to the trust store.

From the SSLLabs report, you can download the complete certificate chain with intermediates and root. Click "Click here to expand" under "Certification Paths", and then click the faint download icon next to the path whose chain you'd like to download. Save this as a .pem file, and its path can be used as the argument to `verify=`. — user85461, Mar 25 '20 at 02:54
The last paragraph helped me solve the error finally. Thank you for mentioning it. — MrObjectOriented, May 17 '22 at 15:51

score 2 · Answer 2 · answered Mar 25 '21 at 20:14

2

cat institution-certificate.pem >> venv/lib/python3.9/site-packages/certifi/cacert.pem

This should solve the problem if your network requires a CA

answered Mar 25 '21 at 20:14

Luiz Felipe Lima

61
2

Since I had my institution's certificate handy, this was the easiest and most robust solution. – redbeam_ Feb 21 '23 at 23:57

score 1 · Answer 3 · answered Nov 25 '22 at 19:56

using the certifi doesn't seem to be implied, so i'll show you what made my solution:

import urllib, urllib2, ssl
import certifi

request = urllib2.Request(url=url)
kw = dict()
if url.startswith('https://'):
    certifi_context = ssl.create_default_context(cafile=certifi.where())
    kw.update(context=certifi_context)
urllib2.urlopen(request, **kw)

i found this solution and more on RealPython, here

score -3 · Answer 4 · answered Mar 09 '22 at 18:34

-3

If you can avoid the certificate verification (not secure), set PYTHONHTTPSVERIFY environment variable to 0:

export PYTHONHTTPSVERIFY=0

This will skip the certificate verification.

answered Mar 09 '22 at 18:34

Adil

2,418
7
34
38

1

Did not work for me. What library uses this variable? `requests` certainly does not. – redbeam_ Feb 18 '23 at 00:50
@redbeam_ This turn certificate verification off which is turned on by default. You can refer https://access.redhat.com/articles/2039753 – Adil Feb 20 '23 at 08:41

kerberos · Answer 5 · 2017-10-06T11:16:35.810

-4

import requests
html = requests.get("https://hcaidcs.phe.org.uk/WebPages/GeneralHomePage.aspx",verify=False).text

You should write it like this, and I've verified it

edited Oct 06 '17 at 11:16

answered Oct 06 '17 at 11:04

kerberos

1,527
2
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If you want to get additional information from the asker, please use the comments. Answers which are just a shot into the blue might get downvoted. – Klaus D. Oct 06 '17 at 11:13
33

This simply disables any kind of certificate validation. This should only be used for testing but never in production since it opens the application to man in the middle attacks. – Steffen Ullrich Oct 06 '17 at 11:29
14

Good enough for home scripting IMO. Good answer – Elliott Beach May 04 '19 at 17:17
2

good answer for self experimentation but i would suggest adding a warning/disclaimer in your answer – mightyandweakcoder Apr 12 '22 at 12:13

Python requests SSL error - certificate verify failed

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