hi, this means that the webserver you're trying to reach is vulnerable to the recently published logjam vulnerability: http://arstechnica.com/security/2015/05/https-crippling-attack-threatens-tens-of-thousands-of-web-and-mail-servers/ please report that to webmaster of the site in question to fix that issue...

Workaround for Firefox 39 and above:

1) In FireFox, enter "about:config" in the URL field and press enter. 2) Accept the "This might void your warranty!" warning :) 3) In the search field at the top, enter "security.ssl3.dhe_rsa_aes" 4) Double click each result (128 and 256) to toggle the Value to "false"

Now retry your site - it should work now. Remember to change these settings back when you're done.

higherdestiny: lifesaver - thank you :)

@higherdestiny: Your solution worked but are there any cons to it?

Thanks

By re-enabling these DHE cipher suites you will make yourself vulnerable to the Logjam attack.

• https://developer.mozilla.org/en-US/Firefox/Releases/39/Site_Compatibility#Security

Except any other way to do this about:config ? i mean in programmatically

You can only do that via the about:config page, but enabling these two cipher suites is not recommended. You should contact the website and ask them to upgrade their security.

Logjam: How Diffie-Hellman Fails in Practice:

• https://weakdh.org/

Users of Firefox releases 38 and older can disable these cipher suites and toggle these prefs to false via this extension:

• Disable DHE: https://addons.mozilla.org/firefox/addon/disable-dhe/

This is not always possible. In my case, the webpage is served by a legacy PCI raid card - I very much doubt the manufacturer will be doing any updates. My only option (if I want to carry on using Firefox!) is to drop the shields, inspect the raid status etc, then raise the shields again. I just hope there are no Klingons about!

Can anyone suggest any other solutions?

Thanks for help!

Peter said

This is not always possible. In my case, the webpage is served by a legacy PCI raid card - I very much doubt the manufacturer will be doing any updates. My only option (if I want to carry on using Firefox!) is to drop the shields, inspect the raid status etc, then raise the shields again. I just hope there are no Klingons about! Can anyone suggest any other solutions?

I would like to hear other suggestions for this as well. I have a couple of internal sites. I used to be able to create an exception for _that_ specific site, without disabling all security, after accepting a number of warnings etc. Now I have to use a different browser.