ControlMQ – Secure communications for control system applications

Can my post get "unflagged" now?

You bring up many valid points.

I won’t say much about crypto at this point other than we plan on having FIPS-140-2 certified crypto in the near future.

Yes, we are using a new protocol, but I don’t agree that it needs to be a full IETF standard. We are working within the standard IP 99 protocol. A protocol is just another piece of code, just like any other part of a systems code base. It just happens that this code talks to code on another machine. Should IETF or others review all code before using? Has all the code you use been so reviewed?

We don’t know if there is a protocol error in the definition of our stuff. If we did, we would fix it. What we did is a careful analysis and design of a highly constrained solution that was then carefully implemented and tested. That’s about as good as a human constructed machine can be built. If errors are found as the protocol is used, we will fix them, provided they are revealed to us. That’s the problem with cybersecurity, you never really know.

You need a peer review of a protocol. OK, but I ask again, does all your code need such a review before you will use it? Or are you singling out network protocols? BTW we are considering making this an open standard for the language and the wireline protocol, but we need to see how this plays out first.

Respectfully, I stand behind my statement that a system can’t be proven secure. I understand that there is a lot of good work going on in provably correct systems using formal methods. And I think that they will help greatly in making systems more correct, but they will never ultimately prove correctness in the mathematical sense. Take the Erlang code, how do you know it’s design is correct? That is, maybe it does exactly the wrong thing. Or that the code testing the Erlang code is correct?

Black box testing is the place to start. Then progressively lighting the testing, from gray to white box is usually recommended. Yes, testing is not perfect, but has defendable arguments about its correctness. Hence, the movement to use test-driven development.

Yes, there is a chance that our product will get hacked. But, that is not the issue. The issue is: will that take more effort, time, money, and resources to do than for what is being used today? We think the answer is yes.

Whether a protocol, or any code, is published or not, it is still vulnerable to being hacked and that hack being kept confidential. The effect is the same.

MQTT is a good example. The payload can be anything, including malware, as in the example where a client gets compromised. Our protocol is highly restricted so that secretly passing malware in a message is highly unlikely.

Again, respectfully, I stand by the statement that security is based on trust. Proof has to be believed to be useful, so you have to trust the source of the proof, and who provides it.

Overall, we believe that our product is simpler and less error prone to configure, and less vulnerable to exploits then assembling all the technologies that have been mentioned here. We are providing just one piece of a cybersecurity framework that only covers controls network communications, as part of an overall cybersecurity plan.

My comment was too long, as deemed by HN. So I posted it here.

https://pastebin.com/hLBbqk24

1. Your reply was "SYN cookies can be a solution, but it has limitations, and to overcome those limitations requires changes to the TCP protocol." Can you tell me more about these limitations? I thought the SYN cookies work pretty well. And they are pretty simple to setup -- in fact, they need no setup at all, as they are already enabled by default in the recent distributions.

2. Right, so how does your protocol solve a padding problem? Why won't this method work with ZeroMQ?

3. As I was saying above, this is still wrong. Both TLS and CurveZMQ are protected against replay attack.

Thanks for the detailed response.

I understand the need to see inside the technology to understand how and why it works. Some of our technology is being patented, so it will be published. Some is trade secrets, so we keep that closely held. These are business decisions that may change in the future as needed. We are considering publishing the protocol on the wire standard and the SIDL language, as so many people will likely want an open standard for these. We don’t believe in “security through obscurity” as that is just delaying the inevitable and fooling ones self. On the other hand, we do have some competitors that may like some of our closely held techniques, which we would rather not share.

The example of the motor controller is a good one, and one that this technology handles well. In the case of a command to set motor speed the interface message specifies the acceptable range of values and the implementation on each side enforces those limits. So, the motor won’t spin beyond its capabilities. These are just the kind of use cases for which the protocol was designed. With regards to RFCs, they are recommendations not specifications per se. That is, a vendor is free to implement the RFC as it sees fit. An offensive cyber operator told me that if you want to hack a network just open the RFCs and search for the word “may” and start there. So, what you get can be very vendor specific.

Our chief concern as to attackers is the nation-state actors. We believe that they have the best techniques and are at the leading edge of cyberoffense capabilities. Unfortunately, there work is highly classified and we only get a glimpse or an innuendo occasionally as to what they do.

One of the features of the technology that really enhances the defensive strength is the use of the highly constrained interface specification. If an attacker on a compromised client tried to shoehorn some malware into a message it would almost certainly get dropped as the bit combination in the message arguments would most likely not pass the constraint validation tests. Thus, the attack surface for the interface is greatly reduced from that allowed by other protocols.

We don’t trust SSL, SSH, and SCP, as we’ve been told not to. We only use these during configuration when we tell users to disconnect the system from the network.

I appreciate the thoughts. Makes me think hard about what we’re doing and how to communicate it.

What about the “flagged”?