We released two new Modbus TCP IDS signatures and some improvements and updates today. The download of the entire new SCADA IDS package and links to the documentation are available on our IDS research page.
The new signatures identify Modbus scanners in two different ways.

SID 1111013, Modbus TCP - Function Code Scan, identifies a scanner attempting [...]

This demo has been making the rounds of the trade shows over the last couple of years. It is both simple and a powerful demonstration for those without an IT background. Basically, the Modbus protocol has virtually no security. It is easy to recover passwords using a sniffer, and in many cases [...]