Expert Techniques for Disabling SSL Certificate Verification in Python Requests

Oct 31, 2023 ยท 7 min read

Requests is the undisputed king of Python libraries for HTTP requests. Its simple API has made it a staple of Python web scraping and API testing.

But the crown is not without its thorns. One common "gotcha" is Requests' built-in verification of SSL certificates.

Trying to make a request to a site with an invalid SSL cert will throw this familiar error:

SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed

Suddenly your scripts grind to a halt. ๐Ÿ˜ซ

Now you could just ignore those useless certs and disabling SSL verification altogether. But don't do that just yet!

That may fix your immediate issue, but it opens up risks down the road. Instead, let's dig into Requests properly and see how to disable verification selectively and securely.

After all, you are a Python professional - no shoddy coding!

In this comprehensive guide, you'll learn:

  • Multiple methods for disabling SSL verification in Requests
  • When and where each technique is appropriate
  • How to avoid common pitfalls and errors
  • Best practices for staying secure
  • So grab your hard hat and let's dig in!

    Why Verify Certificates? A Quick SSL Primer

    First, why does Requests even bother verifying SSL certificates?

    To understand that, we need a quick SSL primer. Feel free to skip ahead if you're already familiar.

    SSL (Secure Sockets Layer) is a security protocol for establishing encrypted links between web servers and clients. That familiar padlock in your browser indicates an SSL connection.

    Part of SSL involves certificates that verify site identities and encrypt traffic. Certs are issued by certificate authorities (CAs) like Digicert or LetsEncrypt.

    They provide validation that you are talking to who you think. This prevents man-in-the-middle attacks.

    Now Requests verifies these certificates by default to protect you. But in some cases, you'll want to disable this. Let's look at the main techniques...

    Method 1: Per-Request Verification Disabling

    The most straightforward way to disable SSL certificate verification is per request via the verify parameter:

    import requests
    
    response = requests.get('<https://invalid-ssl.com>', verify=False)
    

    This disables verification only for this request, keeping all others verified.

    Pros:

  • Simple and targeted.
  • Cons:

  • Can lead to repetitive code when making many requests.
  • Risk of forgetting it and allowing an insecure request.
  • So this method works in a pinch, but we can do better...

    Method 2: Global Verification Disabling

    For more permanent disabling, we can set verify=False globally on the Requests session:

    import requests
    
    session = requests.Session()
    session.verify = False
    
    response = session.get('<https://invalid-ssl.com>')
    

    Now all requests from this session will skip verification.

    Pros:

  • Don't need to keep specifying verify=False.
  • Can selectively enable certs when needed.
  • Cons:

  • Risk of allowing all requests to go insecure.
  • Hard to undo without creating a new session.
  • This is handy for APIs and sites you permanently don't want to validate. But it's a bit sledgehammer-y.

    Method 3: Disabling Those Pesky Warnings

    One downside to disabling verification is the screen full of warnings Requests will spew at you:

    InsecureRequestWarning: Unverified HTTPS request is being made...
    

    We can suppress them with:

    from urllib3.exceptions import InsecureRequestWarning
    requests.packages.urllib3.disable_warnings(category=InsecureRequestWarning)
    

    But note warnings exist for a reason - to alert you to potential security issues. I'd recommend only disabling them once you're done testing.

    Method 4: Using a Custom Certificate

    Another option is to provide your own custom PEM certificate:

    custom_cert = '/path/to/mycert.pem'
    
    response = requests.get('<https://self-signed.com>', verify=custom_cert)
    

    This can be useful for internal servers using self-signed certs.

    Pros: More secure than disabling verify altogether.

    Cons: Need to have cert access and management.

    Method 5: Set Environment Variable

    Finally, we can specify a custom cert via the REQUESTS_CA_BUNDLE environment variable:

    import os
    os.environ['REQUESTS_CA_BUNDLE'] = '/path/to/cacert.pem'
    
    response = requests.get('<https://example.com>')
    

    This keeps the custom cert out of your code.

    Pros: Avoid hardcoded custom cert paths.

    Cons: More convoluted setup.

    So in summary, we have many options - per request, global, warnings, custom certs, and environment. Choose wisely based on your use case!

    Should You Disable Verification? Dangers & Best Practices

    Before you go disabling that vital SSL verification, let's recap the security implications.

    Disabling SSL cert verification weakens security by removing a key validation step. Doing so on production systems can be dangerous and open you to MITM attacks.

    So in general, only disable verification in development/testing on trusted networks. Make sure you re-enable it before going live. The goal should be to fix the root certificate issue rather than simply bypassing it indefinitely.

    Other best practices include:

  • Use per-request disabling over global where possible.
  • Suppress warnings only temporarily during testing.
  • Rotate custom certs periodically if using them.
  • Validate custom certs come from expected CAs.
  • Only send non-sensitive data when verification is off.
  • Following these tips will keep you secure even as you temporarily work around SSL issues.

    Other Concerns When Disabling Verification

    Let's round out this guide by looking at a few other things to keep in mind:

  • Python version - The methods may differ slightly between Python 2 and 3. Always check official docs.
  • Other libraries - Projects like Selenium may reject self-signed certs even if you disable in Requests.
  • Corporate proxies - Will sometimes intercept traffic and add their own certs.
  • VM traffic - Calls between virtual machines often fail cert verification since certs are self-signed.
  • API testing - Great case to use disabling while testing against dev environments.
  • Web scraping - More risk since you don't control the sites being scraped.
  • The main takeaway is test in your specific environment. What works for one setup may fail in another. Always validate you are getting the expected behavior.

    Conclusion and Key Takeaways

    And there you have it - my insider's guide to proficiently disabling SSL certificate verification in Python's Requests library!

    We looked at:

  • Five different methods to disable verification
  • Use cases where disabling is beneficial
  • Dangers of disabling and how to mitigate risks
  • Special cases and troubleshooting odd behavior
  • The key takeaways are:

  • Use disabling judiciously - it comes with risks.
  • Employ best practices like short-term use and rotating certs.
  • Test rigorously and be aware of your environment.
  • Fix the root problem where possible rather than relying on disabling.
  • Employing these lessons will make you a verification expert in no time!

    Now go forth and request securely. ๐Ÿ‘ And let me know if you have any other tips!

    Frequently Asked Questions

    Here are answers to some common questions about disabling SSL certificate verification in Python Requests:

    How can I disable verification for just one request?

    Pass verify=False in the request method like requests.get(url, verify=False).

    What's the quickest way to disable verification globally?

    Set verify=False on a Requests Session object like session.verify = False.

    Why am I still seeing SSL warnings after disabling verification?

    You need to explicitly disable InsecureRequestWarning with urllib3.

    What if I want to use my own certificate?

    You can pass the PEM cert path to verify like verify='/path/to/mycert.pem'.

    How do I avoid hardcoded certificate paths in my code?

    Set the REQUESTS_CA_BUNDLE environment variable to the cert location.

    Is disabling verification risky?

    Yes, it removes a security validation step so only do it temporarily in development.

    What if I'm making requests between my own machines?

    Self-signed certs on internal servers can cause issues. Use a custom cert.

    How can I validate that my cert is properly disabled?

    Always test your requests to confirm no errors occur from verification failures.

    Hopefully these answers provide a quick reference on key points around disabling SSL certificate verification in Python Requests.

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