Disabling SSL Certificate Verification in Python Requests

In this tutorial, we will explore how to disable SSL certificate verification when using the requests library in Python. This is often necessary when working with servers that have expired or invalid certificates.

Introduction to SSL Certificate Verification

When you send an HTTPS request, the server responds with its SSL/TLS certificate, which contains its public key and identity information. The client (in this case, your Python script) verifies the certificate by checking its validity period, issuer, and subject. If the verification fails, the client raises an SSLError.

Disabling Certificate Verification

To disable certificate verification in requests, you can pass the verify=False parameter to the request method. For example:

import requests

response = requests.get('https://example.com', verify=False)

By setting verify=False, you are telling requests not to check the server’s certificate. This can be useful for testing or development purposes, but it is not recommended for production use, as it makes your application vulnerable to man-in-the-middle attacks.

Suppressing InsecureRequestWarning

When you set verify=False, urllib3 (which is used by requests) raises an InsecureRequestWarning. To suppress this warning, you can use the following code:

import requests
import urllib3

urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)

response = requests.get('https://example.com', verify=False)

Alternatively, you can use a context manager to disable warnings only for a specific block of code:

with urllib3.warnings.catch_warnings():
    urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
    response = requests.get('https://example.com', verify=False)

Using a Session Object

If you need to make multiple requests with disabled certificate verification, it’s more efficient to use a Session object. You can set the verify attribute on the session object:

import requests

session = requests.Session()
session.verify = False

response1 = session.get('https://example.com')
response2 = session.post('https://example.com', data={'key': 'value'})

Important Security Considerations

Disabling certificate verification makes your application vulnerable to man-in-the-middle attacks. An attacker can intercept and modify the traffic between your client and the server, potentially stealing sensitive information or injecting malware.

Therefore, it’s essential to use disabled certificate verification only for testing or development purposes, and never in production environments. Always ensure that the server’s certificate is valid and trusted before sending sensitive data.

Conclusion

In this tutorial, we learned how to disable SSL certificate verification in Python requests using the verify=False parameter. We also explored how to suppress the InsecureRequestWarning raised by urllib3. While disabled certificate verification can be useful for testing purposes, it’s crucial to prioritize security and use trusted certificates in production environments.