SSLv3 is now insecure, and is soon going to be disabled by default.
https://blog.mozilla.org/security/2014/10/14/the-poodle-attack-and-the-end-of-ssl-3-0/In the meantime, you can use this extension to turn off SSLv3 in your copy of Firefox. When you install the add-on, it will set the minimum TLS version to TLS 1.0 (disabling SSLv3). If you want to change that setting later, like if you really need to access an SSLv3 site, just go to Tools / Add-ons and click the "Preferences" button next to the add-on. That will give you a drop-down menu to select the minimum TLS version you want to allow.
As of version 0.2, this add-on should work with all Mozilla products, including Firefox, Firefox for Android, Thunderbird, and Seamonkey.
Add-ons
