I believe that this patch to the NSS 3.19.1 was when this is enabled. Is your NSS version (listed in about:support page)?

Yes those prefs have been disabled in the current Firefox beta release.

• security.ssl3.dhe_rsa_aes_128_sha
• security.ssl3.dhe_rsa_aes_256_sha

See also:

• bug 1166031 - Update to NSS 3.19.1

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...

See also:

• https://weakdh.org/

The problem can be solved by downgradeing the following libraries: nss nss-sysinit nss-util nss-softokn nss-softokn-freebl nss-tools nss-sysinit

[code]

1. dnf downgrade nss nss-sysinit nss-util nss-softokn nss-softokn-freebl nss-tools nss-sysinit

/code

http://www.forum.internettechnology.ro/viewtopic.php?f=10&t=40&sid=7f8efac987c57f1ad48a2c94e249fe6f

Solved with the new update of NSS* libraries. New version nss-*-3.19.2.

cor-el said

Yes those prefs have been disabled in the current Firefox beta release.

• security.ssl3.dhe_rsa_aes_128_sha
• security.ssl3.dhe_rsa_aes_256_sha

See also:

• bug 1166031 - Update to NSS 3.19.1

Sadly, I need to turn these off because our network administrator runs a server that is vulnerable to logjam and absolutely necessary to my day-to-day and hour-to-hour job duties. Not being able to connect to it right out of the gate w/o fiddling with the config settings was probably a smart idea for the masses, but a smart mass like me needs to get on with things. Maybe an exception page for this is worth considering?

Maybe use a second profile that has the prefs set to true to access these pages.

• https://developer.mozilla.org/Mozilla/Multiple_Firefox_Profiles

Can someone put this in plain English? I can't log on to our United employee website with the latest Firefox (I am up to date) without getting the error mentioned in the first post (An error occurred during a connection to 192.168.1.24:2400. SSL received a weak ephemeral Diffie-Hellman key in Server Key Exchange handshake message. (Error code: ssl_error_weak_server_ephemeral_dh_key) ).

Hi OnTheRoad41, this error message indicates that the site is trying to use an obsolete encryption cipher which is vulnerable to the "Logjam" attack that was in the news earlier this year.

What does that mean?

Even though you trust the server, a "Logjam" attack compromises the security of your individual connection to the server, lowering the protection normally provided by SSL to a level that is easily cracked and read by others on the network. That is why Firefox protects you from making this connection.

What can you do now?

The very best solution for the protection of all users of that server is for United to change some settings on the server. If the information you can view on the server is sensitive, then this fix is overdue, so we encourage you to report the problem ASAP.

If you cannot wait, you can try disabling these old ciphers in your Firefox, which hopefully will force the server to try some more secure ciphers when connecting with you. Here's how:

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the search box above the list, type or paste dhe and pause while the list is filtered

(3) Double-click the security.ssl3.dhe_rsa_aes_128_sha preference to switch it from true to false (disable Firefox from using this cipher)

(4) Double-click the security.ssl3.dhe_rsa_aes_256_sha preference to switch it from true to false (disable Firefox from using this cipher)

Then try the site again; you might have to reload the page using Ctrl+Shift+r to bypass cached information.

Success?

Thanks! That solved the problem of not being able to logon. United is notorious for not being friendly to computer users. They have their protocols, thank you very much, so don't bother them.

Thanks again.

Hope your problem is solved now.