Wednesday, July 26, 2017

Oracle Mobile Cloud Service (MCS) and Integration Cloud Service (ICS): How secure is your TLS connection?

In a previous blog I have explained which what cipher suites are, the role they play in establishing SSL connections and have provided some suggestions on how you can determine which cipher suite is a strong cipher suite. In this blog post I'll apply this knowledge to look at incoming connections to Oracle Mobile Cloud Service and Integration Cloud Service. Outgoing connections are a different story altogether. These two cloud services do not allow you control of cipher suites to the extend as for example Oracle Java Cloud Service and you are thus forced to use the cipher suite Oracle has chosen for you.

Why should you be interested in TLS? Well, 'normal' application authentication uses tokens (like SAML, JWT, OAuth). Once an attacker obtains such a token (and no additional client authentication is in place), it is more or less free game for the attacker. An important mechanism which prevents the attacker from obtaining the token is TLS (Transport Layer Security). The strength of the provided security depends on the choice of cipher suite. The cipher suite is chosen by negotiation between client and server. The client provides options and the server chooses the one which has its preference.

Disclaimer: my knowledge is not at the level that I can personally exploit the liabilities in different cipher suites. I've used several posts I found online as references. I have used the OWASP TLS Cheat Sheet extensively which provides many references for further investigation should you wish.

Monday, July 3, 2017

SSL/TLS: How to choose your cipher suite

For SSL/TLS connections, cipher suites determine for a major part how secure the connection will be. A cipher suite is a named combination of authentication, encryption, message authentication code (MAC) and key exchange algorithms used to negotiate the security settings (here). But what does this mean and how do you choose a secure cipher suite? The area of TLS is quite extensive and I cannot cover it in its entirety in a single blog post but I will provide some general recommendations based on several articles researched online. At the end of the post I'll provide some suggestions for strong ciphers for JDK8.