Running a vulnerability scanner on a hybrid network segment that includes general IT servers and industrial control systems:

While a vulnerability scanner might detect vulnerabilities related to Modbus (if it has specific checks), the primary and more severe risk of scanning ICS is operational disruption, not just the revelation of protocol-specific flaws.

Industrial Control Systems (ICS) are often highly sensitive to network traffic, especially the intensive and sometimes malformed packets generated by vulnerability scanners, which can lead to unintended failures, system crashes, or disruption of critical operations. These systems are not designed with the same robustness against scanning as general IT infrastructure.

Running a vulnerability scanner on a diverse segment (IT and ICS) does not inherently reduce the true positive rate; it might increase false positives or negatives, but unintended failures is a more direct and critical concern for ICS.

While a denial-of-service could occur, "unintended failures" is a broader and more accurate description of the typical severe consequences for delicate ICS components, which can involve physical process disruption, not just network unavailability.