Disabling RC4 in Firefox
Firefox users can turn off RC4 in the web browser completely. It needs to be noted that some secure sites may fail to work after doing so.
1)Type about:config in the browser’s address bar and hit enter.
2)Confirm you will be careful if you receive a prompt.
3)Search for RC4 and double-click on the following preferences to set them to false.
4)security.ssl3.ecdhe_ecdsa_rc4_128_sha
5)security.ssl3.ecdhe_rsa_rc4_128_sha
6)security.ssl3.rsa_rc4_128_md5
7)security.ssl3.rsa_rc4_128_sha
Once you have made the changes reload the test page linked above. You should get connection failure messages instead of warnings when you do that.
If you run into issues connecting to secure sites after making the changes you may need to restore support for RC4. To do that repeat the steps above and make sure the values of the preferences are set to true afterwards.