Attack of the week: Logjam

If you are using Debian 7 or similar distro with an older version of Apache you can avoid it by using the following ciphers[1]:

SSLCipherSuite ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-DSS-AES128-SHA256:DHE-DSS-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA:!DHE-RSA-AES128-GCM-SHA256:!DHE-RSA-AES256-GCM-SHA384:!DHE-RSA-AES128-SHA256:!DHE-RSA-AES256-SHA:!DHE-RSA-AES128-SHA:!DHE-RSA-AES256-SHA256:!DHE-RSA-CAMELLIA128-SHA:!DHE-RSA-CAMELLIA256-SHA

However if you are using Apache 2.4.8 or later just follow the instructions here[2]

Either should get you an "A" on SSL labs test[3]

[1] http://serverfault.com/questions/693306/trying-to-mitigate-l...

[2] https://weakdh.org/sysadmin.html

[3] https://www.ssllabs.com/ssltest/analyze.html

I encourage all people to check their website. On our checker (http://security.uwsoftware.be/logjam) we see that 59% is still vulnerable (<= 1024 key). Even after checking most people don't upgrade. Note: the solution isn't that difficult (see https://weakdh.org/sysadmin.html)

What is also fun is that neither IE or Netscape support DHE_RSA_EXPORT, and they didn't bother with DHE_RSA_EXPORT1024 at all (only DHE_DSS_EXPORT1024).