Configure Spring Boot to Prevent Logjam Attack - spring

Question

Firefox v39 will no longer connect to my web application over HTTPS. I'm using Spring Boot with embedded Tomcat and I've made sure I'm using the latest version of Boot (v1.2.5). Firefox shows the following error message:
Secure Connection Failed
An error occurred during a connection to [website]. SSL received a weak ephemeral Diffie-Hellman key in Server Key Exchange handshake message. (Error code: ssl_error_weak_server_ephemeral_dh_key)
I understand this is to protect against a known vulnerability called Logjam. A solution for Tomcat is provided at weakdh.org.
Spring Boot passes SSL configuration to Tomcat via application.properties and as such I have added server.ssl.ciphers to my application.properties as follows:
server.port=443
server.ssl.key-store=/home/ec2-user/boot.p12
server.ssl.key-store-password=...
server.ssl.keyStoreType=PKCS12
server.ssl.keyAlias=...
server.ssl.ciphers=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_DHE_RSA_WITH_AES_128_GCM_SHA256,TLS_DHE_DSS_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_SHA256,TLS_ECDHE_RSA_WITH_AES_128_SHA,TLS_ECDHE_ECDSA_WITH_AES_128_SHA,TLS_ECDHE_RSA_WITH_AES_256_SHA384,TLS_ECDHE_ECDSA_WITH_AES_256_SHA384,TLS_ECDHE_RSA_WITH_AES_256_SHA,TLS_ECDHE_ECDSA_WITH_AES_256_SHA,TLS_DHE_RSA_WITH_AES_128_SHA256,TLS_DHE_RSA_WITH_AES_128_SHA,TLS_DHE_DSS_WITH_AES_128_SHA256,TLS_DHE_RSA_WITH_AES_256_SHA256,TLS_DHE_DSS_WITH_AES_256_SHA,TLS_DHE_RSA_WITH_AES_256_SHA
After restarting boot, I notice the following in my log file:
WARN 2674 [main] --- o.a.t.util.net.jsse.JSSESocketFactory : None of the ciphers specified are supported by the SSL engine : TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, ...
Additionally, connecting using Firefox fails with the following message:
Secure Connection Failed
The connection to [website] was interrupted while the page was loading.
And I see the following in my log file:
javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)
Unfortunately I'm no encryption expert. Can anyone suggest how to fix this? Do I need to recreate my HTTPS certificate?

Answer 1

The solution was to upgrade server Java on the server from 1.7 to 1.8.
sudo yum remove java-1.7.0-openjdk
sudo yum install java-1.8.0
After this was complete, no other configuration was necessary. Not even modyfing Tomcat as per the advice at weakdh.org.