SoylentNews

kaszz writes:

There's a new TLS protocol security vulnerability found that can be exploited using protocol downgrade that was left in place due to previous U.S. government export restrictions its been named "Logjam". It affects servers supporting the Diffie-Hellman key exchange, and it's caused by export restrictions mandated by the U.S. government during the Clinton administration. "Attackers with the ability to monitor the connection between an end user and a Diffie-Hellman-enabled server that supports the export cipher can inject a special payload into the traffic that downgrades encrypted connections to use extremely weak 512-bit key material. Using precomputed data prepared ahead of time, the attackers can then deduce the encryption key negotiated between the two parties."

Internet Explorer is the only browser yet updated to block such an attack — patches for Chrome, Firefox, and Safari are expected soon. The researchers add, "Breaking the single, most common 1024-bit prime used by web servers would allow passive eavesdropping on connections to 18% of the Top 1 Million HTTPS domains. A second prime would allow passive decryption of connections to 66% of VPN servers and 26% of SSH servers. A close reading of published NSA leaks shows that the agency's attacks on VPNs are consistent with having achieved such a break." Here is their full technical report (PDF).

Time for a complete overhaul?

[Update: Thanks to Canopic Jug for locating and providing a link to the Common Vulnerabilities and Exposures entry CVE-2015-4000; check there for official information and updates.]