FREAK Attack Threatens SSL Clients

msm1267 writes: For the nth time in the last couple of years, security experts are warning about a new Internet-scale vulnerability, this time in some popular SSL clients. The flaw allows an attacker to force clients to downgrade to weakened ciphers and break their supposedly encrypted communications through a man-in-the-middle attack. Researchers recently discovered that some SSL clients, including OpenSSL, will accept weak RSA keys–known as export-grade keys–without asking for those keys. Export-grade refers to 512-bit RSA keys, the key strength that was approved by the United States government for export overseas. This was an artifact from decades ago and it was thought that most servers and clients had long ago abandoned such weak ciphers. The vulnerability affects a variety of clients, most notably Apple's Safari browser.

Comments

Re:Is there any way to block the use of old cipher

[chill]

Yes. http://www.openssl.org/docs/apps/ciphers.html

The question is does OpenSSL accept the weak ciphers as a downgrade bug even when EXPLICITLY DISALLOWD.

I haven't seen answered in any of the linked articles so am digging/testing.

After the last couple of bugs my organization set the explicit cipher/algorithm/has acceptable list. The export ciphers were excluded on purpose from our list.

SSL Labs https://www.ssllabs.com/ has a recommended list buried in their documentation somewhere.