SSLv2Hello - javax.net.ssl.SSLException: Received

Question

I am trying to call an SSL protected web service running on JDK7 / WildFly 8.2 with a Java 6 (update 31) based client.

The first problem I encountered on the client was:

javax.net.ssl.SSLException: Received fatal alert: unexpected_message

By setting javax.net.debug to all on both sides, I got the following hint on the server side:

javax.net.ssl.SSLHandshakeException: SSLv2Hello is disabled

Quick research shows that,

SSLv2Hello disabled by default on the client: In Java SE 7, SSLv2Hello is removed from the default enabled protocol list on the client.

So I have tried to enable SSLv2Hello on WildFly in standalone.xml:

<https-listener name="https" 
                socket-binding="https" 
                security-realm="UndertowRealm"
                enabled-protocols="SSLv2, SSLv2Hello, TLSv1, TLSv1.1, TLSv1.2"
                />

And the result on the server is:

javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)

So I realize, I should be trying to force TLS on the client instead of enabling SSLv2Hello on the server. I have tried to set System.setProperty("https.protocols", "TLSv1"); before my web service call with no effect.

What should I configure and how, to get the handshake working?

I have printed the supported cipher suites from the default SSLSocketFactory on the server:

TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
TLS_RSA_WITH_AES_128_CBC_SHA,
TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA,
TLS_ECDH_RSA_WITH_AES_128_CBC_SHA,
TLS_DHE_RSA_WITH_AES_128_CBC_SHA,
TLS_DHE_DSS_WITH_AES_128_CBC_SHA,
TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA,
TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
SSL_RSA_WITH_3DES_EDE_CBC_SHA,
TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA,
TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA,
SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA,
SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA,
TLS_ECDHE_ECDSA_WITH_RC4_128_SHA,
TLS_ECDHE_RSA_WITH_RC4_128_SHA,
SSL_RSA_WITH_RC4_128_SHA,
TLS_ECDH_ECDSA_WITH_RC4_128_SHA,
TLS_ECDH_RSA_WITH_RC4_128_SHA,
SSL_RSA_WITH_RC4_128_MD5,
TLS_EMPTY_RENEGOTIATION_INFO_SCSV

Answer 1

You don't need to enable SSLv2 at the server. You need to disable the SSLv2Hello pseudo-protocol at the client, by removing SSLv2Hello from the enabled TLS protocols and leaving the others:

System.setProperty("https.protocols", "TLSv1,TLSV1.1,TLSV1.2");

and maybe SSLv3 if that makes it happy: it won't for much longer, so try not to have to do that.

Note that it is a pseudo-protocol. It is not SSLv2, it is a compatibility measure to allow certain arguably broken servers to accept the hello. The session however operates at SSLv3 or above. It is also obsolete.

Answer 2

You could probably enable the SSLv2 protocol at the JVM but that is extremely inadvisable because that is a serious security risk.

The clients are using an outdated and insecure protocol and should be updated to TLSv1.1 or TLSv.1.2. That will require at least Java 7 but Java 8 would be better as Robert mentioned.

More info could be found at https://blogs.oracle.com/java-platform-group/entry/diagnosing_tls_ssl_and_https including a table of support TLS protocols by version.