I was wondering if anyone can give me any information on security with Modbus-TCP. Is there any? It doesn't seem to be mentioned in any of the documents I have read.

If one were to use a wireless ethernet solution, how would you eliminate the possibility of someone from intercepting your network traffic?

Thanks,

 

That would be the function of the transport. Look at PVN, frequency diverse and transparent encryption solutions. With the exception of
frequency diversity, which does make it difficult to intercept, the solutions center around making it difficult to interpret. Frequency diversity can be quite good if the sequences are changed often and unpredictably.

Regards

cww

 

The Modbus part of Modbus/TCP doesn't have any security - that's up to the implementation of the TCP/IP system.

For a wireless 802.11B system, you could use the WEP security. As I'm sure others will point out, there are a couple of different levels of this, with different key lengths. If you're concerned you'd probably want the 128 bit key length.

Other wireless systems, like spread spectrum and Bluetooth, I'll leave up to somebody else to answer.

Kenneth Schunk
Graybar Electric Company


> I was wondering if anyone can give me any information on security with Modbus-TCP. Is there any? It doesn't seem to be mentioned in any of the documents I have read.
>
> If one were to use a wireless ethernet solution, how would you eliminate the possibility of someone from intercepting your network traffic?
>
> Thanks,

 

i am coding a modbus 'gsteway' from TCP/IP <-> serial with builtin security... need more info?

 

There are no security features generic within the Modbus TCP protocol. Some manufacturers such as Eurotherm have implemented username/password security. The Modbus TCP master device must first send an encrypted username/password to the 5000 series recorder/logger to confirm the connection prior to any Modbus TCP requests being accepted by the device.

Security/encryption can (should) be implemented in the TCP layer by the appropriate use of the security features (most people don't use it! within routers/wireless access points etc.

Neville Child
Eurotherm Ltd.
[email protected]

 

There are also some industrial security products out there which monitor for security violations and can isolate your control network. The Industrial Defender product from Verano has Modbus security rules I believe.

Dr.John