Adding Security Exception in Mozilla Firefox

This section provides a tutorial example on how to add a security exception in Mozilla Firefox to continue visiting an HTTPS Website with an un-trusted certificate.

What should you do when Mozilla Firefox tells you that "Your connection is not secure"? My suggestions is:

On previous versions of Mozilla Firefox, you can click the "Add Exception..." on the certificate error page. But that button is removed now on FireFox 61.

So I have to the go to the Certificate Manager to add Yahoo's certificate as an exception.

1. Repeat steps listed in the previous tutorial until you see the Certificate Manager dialog box.

2. Go to the "Servers" tab and click the "Add Exception" button. The "Add Security Exception" dialog box shows up.

3. Enter "https://login.yahoo.com" and click "Get Certificate" button. The "Unknown Identify" error shows up.

4. Click the "Confirm Security Exception" button. The "*.login.yahoo.com" certificate is temporarily installed as a trusted certificate.

Add Security Exception - Mozilla Firefox
Adding Security Exception in Mozilla Firefox

5. Go back to visit https://login.yahoo.com. Surprisingly, I am still getting the same certificate error!

This seems to be a bug in Mozilla Firefox. There is no way to add a server certificate exception, until the bug is fixed.

The only way now is to re-install the root CA certificate as described in the next section.

Table of Contents

 About This Book

 Introduction of PKI (Public Key Infrastructure)

 Introduction of HTTPS (Hypertext Transfer Protocol Secure)

 Using HTTPS with Google Chrome

Using HTTPS with Mozilla Firefox

 Visiting "https" Website with Mozilla Firefox

 Viewing Server Certificate in Mozilla Firefox

 Server Certificate General Information

 Viewing Server Certificate Path in Mozilla Firefox

 Exporting Server Certificate to File in Mozilla Firefox

 Viewing Pre-Installed Certificates in Mozilla Firefox

 Listing of Trusted Root CA in Mozilla Firefox

 Exporting Certificate to File from Mozilla Firefox

 Deleting Root CA Certificates from Mozilla Firefox

 Mozilla Firefox Displaying Certificate Error Page

Adding Security Exception in Mozilla Firefox

 Failing to Import Root CA Certificates to Mozilla Firefox

 Certificate Trust Settings in Mozilla Firefox

 HTTPS with Microsoft Edge

 Using HTTPS with Apple Safari

 HTTPS with IE (Internet Explorer)

 Android and Server Certificate

 iPhone and Server Certificate

 Windows Certificate Stores and Console

 RDP (Remote Desktop Protocol) and Server Certificate

 macOS Certificate Stores and Keychain Access

 Perl Scripts Communicating with HTTPS Servers

 PHP Scripts Communicating with HTTPS Servers

 Java Programs Communicating with HTTPS Servers

 .NET Programs Communicating with HTTPS Servers

 CAcert.org - Root CA Offering Free Certificates

 PKI CA Administration - Issuing Certificates

 Comodo Free Personal Certificate

 Digital Signature - Microsoft Word

 Digital Signature - OpenOffice.org 3

 S/MIME and Email Security

 PKI (Public Key Infrastructure) Terminology

 Outdated Tutorials

 References

 Full Version in PDF/EPUB