A bit of vinegar to go with the SOAP.

Not long ago I wrote a 3-part series on using SOAP over HTTPS with ColdFusion. My final solution was to create Java objects directly, bypassing ColdFusion’s CFHTTP tag.

I have since found a subtle flaw with this implementation.

It’s not in the code, but in the  JVM. ColdFusion 8 ships with an older JVM. I recently upgraded our JVM to a more current version in an attempt to resolve a timezone bug. In doing so my SOAP application stopped working.

A little research led me to this article about a TLS bug in Java that could lead to a man-in-the-middle exploit. It appears the way I’m performing my SOAP operation triggers a TLS/SSL renegotiation when it receives a response from the external server.

The short answer is to add the following line to ColdFusion’s JVM arguments:

-Dsun.security.ssl.allowUnsafeRenegotiation=true

This does resolve the problem, but it apparently leaves the JVM vulnerable to MITM attacks. There is another bit of code in that article which shows how to change the allowUnsafeRenegotiation flag on-the-fly. I added this to my ColdFusion code, but changing the flag didn’t appear to have any effect.

If anyone else has played around with this particular problem I’d love to hear about it.

For now I”ve left the JVM in its vulnerable state as we only make HTTP requests from the JVM for a couple of applications and neither of them carry personally identifiable information.

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