Outdated: Adding Security Exception in Firefox 35

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:

Here is what I did to add a security exception to pass the error page:

1. Open Mozilla Firefox to visit to https://login.yahoo.com again and wait for the error page.

2. Click the link "I Understand the Risks". Mozilla Firefox displays more warning messages:

If you understand what's going on, you can tell Firefox to start
trusting this site's identification. Even if you trust the site,
this error could mean that someone is tampering with your connection.

Don't add an exception unless you know there's good reason why this
site doesn't use trusted identification.

[ Add Exception... ]

3. Click the "Add Exception" button. The "Add Security Exception" dialog box shows up:

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

4. Read messages on the dialog box carefully:

You are about to override how Firefox identifies this site.
Legitimate banks, stores, and other public sites will not ask
to do this.

Server Location: https://login.yahoo.com/...

Certificate Status - This site attempts to identify itself with
invalid information.

Unknown Identity - Certificate is not trusted, because it hasn't
been verified by a recognized authority.

[ ] Permanently store this exception

5. Click the "Confirm Security Exception" button. The Yahoo login page shows up.

I could continue to login to my Yahoo account and access my email box if I want to, because I can trust the Yahoo site.

Note that I left the "Permanently store this exception" checkbox unchecked, because I don't want Firefox to remember this exception. When I close Firefox and open it to visit https://login.yahoo.com, I want to see the error page again.

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

 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

 Outdated: Viewing Server Certificate in Chrome 40

 Outdated: Viewing Server Certificate in Firefox 35

 Outdated: Viewing Pre-Installed Certificates in Firefox 35

 Outdated: Firefox 35 Displaying Certificate Error Page

Outdated: Adding Security Exception in Firefox 35

 Outdated: Windows XP Component "Update Root Certificates"

 Outdated: Creating Certificates Console on Windows XP

 Outdated: Applying Digital Signatures with Word 2007

 OutDated: Creating a Digital ID and Sign Word Documents

 OUtdated: Viewing Digital ID Created by MS Word

 Outdated: Obtaining a Trial Digital ID from ARX CoSign

 Outdated: Viewing Digital ID Obtained from ARX CoSign

 Outdated: Windows XP Component - Removing "Update Root Certificates"

 Outdated: IE 8 Displaying Certificate Error Page

 Outdated: IE 8 Displaying Certificate Error Icon

 Outdated: Viewing Certificate Path Validation Error in IE 8

 Outdated: Importing Root Certificate from a File to IE 8

 References

 Full Version in PDF/EPUB