Modify Parameter
Where this stands
No Sigma rule can address this — the telemetry MITRE names has no Sigma logsource behind it.
Sigma has no logsource taxonomy for ICS. MITRE's telemetry here is operational historians and controller state, which no Sigma rule can address.
What the technique is
Adversaries may modify parameters used to instruct industrial control system devices. These devices operate via programs that dictate how and when to perform actions based on such parameters. Such parameters can determine the extent to which an action is performed and may specify additional options. For example, a program on a control system device dictating motor processes may take a parameter defining the total number of seconds to run that motor. An adversary can potentially modify these parameters to produce an outcome outside of what was intended by the operators. By modifying system and process critical parameters, the adversary may cause Impact to equipment and/or control processes. Modified parameters may be turned into dangerous, out-of-bounds, or unexpected values from typical operations. For example, specifying that a process run for more or less time than it should, or dictating an unusually high, low, or invalid value as a parameter.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN1908
Monitor asset management systems for device configuration changes which can be used to understand expected parameter settings. Monitor device application logs parameter changes, although not all devices will produce such logs. Monitor for device alarms produced when parameters are changed, although not all devices will produce such alarms. Monitor ICS management protocols for parameter changes, including for unexpected values, changes far exceeding standard values, or for parameters being changed in an unexpected way (e.g., via a new function, at an unusual time).
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.