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.
| ID | Name | Description |
|---|---|---|
| C0066 | 2026 U.S. Water Utilities Attacks |
During the 2026 U.S. Water Utilities Attacks, the adversary changed the IP addresses of internet-facing MicroLogix controllers, altering their network configuration settings outside normal operations.[1][2][3][4] |
| S1165 | FrostyGoop |
FrostyGoop allows for the modification of system settings by reading and writing to registers via Modbus commands.[5][6] |
| C0041 | FrostyGoop Incident |
In FrostyGoop Incident, the adversary caused the victim controllers to report incorrect measurements by modifying parameters.[5] |
| S1045 | INCONTROLLER |
INCONTROLLER can use the HTTP CGI scripts on Omron PLCs to modify parameters on EtherCat connected servo drives.[7] |
| S1072 | Industroyer2 |
Industroyer2 modifies specified Information Object Addresses (IOAs) for specified Application Service Data Unit (ASDU) addresses to either the ON or OFF state.[8][9] |
| C0020 | Maroochy Water Breach |
In the Maroochy Water Breach, the adversary gained remote computer access to the control system and altered data so that whatever function should have occurred at affected pumping stations did not occur or occurred in a different way. The software program installed in the laptop was one developed for changing configurations in the PDS computers. This ultimately led to 800,000 liters of raw sewage being spilled out into the community.[10] |
| S0603 | Stuxnet |
In states 3 and 4 Stuxnet sends two network bursts (done through the DP_SEND primitive). The data in the frames are instructions for the frequency converter drives. For example one of the frames contains records that change the maximum frequency (the speed at which the motor will operate). The frequency converter drives consist of parameters, which can be remotely configured via Profibus. One can write new values to these parameters changing the behavior of the device. [11] |
| ID | Mitigation | Description |
|---|---|---|
| M0947 | Audit |
Provide the ability to verify the integrity and authenticity of changes to parameter values. |
| M0800 | Authorization Enforcement |
All field controllers should restrict the modification of parameter values to only certain users (e.g., engineers, field technician), preferably through implementing a role-based access mechanism. They should also restrict online edits and enable write protection for parameters. |
| M0804 | Human User Authentication |
All field controllers should require that user authenticate for all remote or local management sessions. The authentication mechanisms should also support Account Use Policies, Password Policies, and User Account Management. |
| M0818 | Validate Program Inputs |
Devices and programs should validate the content of any remote parameter changes, including those from HMIs, control servers, or engineering workstations.[12] |
| ID | Name | Analytic ID | Analytic Description |
|---|---|---|---|
| DET0776 | Detection of Modify Parameter | AN1908 |
Real-time monitoring identifies an Industrial Control System (ICS) protocol write to a parameter/setpoint register where the written value falls outside the documented safe operating range, or where the write originates from a source not in the approved write-source list, correlated with subsequent historian tag drift. Documented precedent: FrostyGoop directly modified Modbus holding register values on ENCO heating controllers in Lviv, Ukraine, causing a two-day remediation outage. OT operational-fidelity gate: Alert only when the action is not attributable to an authorized operator/engineering source for the specific target and function, and it is either outside an approved change/maintenance window or lacks matching change-control context; where telemetry permits, require corroborating device, configuration, or process-state effect. Suppress activity that fully matches approved maintenance, commissioning, failover, recovery, or tested control procedures. |
| AN2145 |
Real-time monitoring identifies a Linux process invoking Industrial Control System (ICS) vendor write Application Programming Interfaces (APIs) or Open Platform Communications (OPC) Unified Architecture (UA) write calls to setpoint tags on field devices, from a User Identifier (UID) not associated with the authorized control application, with values exceeding the safe operating range. OT operational-fidelity gate: Alert only when the action is not attributable to an authorized operator/engineering source for the specific target and function, and it is either outside an approved change/maintenance window or lacks matching change-control context; where telemetry permits, require corroborating device, configuration, or process-state effect. Suppress activity that fully matches approved maintenance, commissioning, failover, recovery, or tested control procedures. |
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| AN2209 |
Real-time monitoring identifies a process on an Industrial Control System (ICS) Windows host writing setpoint values to Open Platform Communications (OPC) Data Access (DA)/Unified Architecture (UA) tags or historian writable tags without being the recognized Supervisory Control and Data Acquisition (SCADA) or Distributed Control System (DCS) control application, with values falling outside the normal operating range. OT operational-fidelity gate: Alert only when the action is not attributable to an authorized operator/engineering source for the specific target and function, and it is either outside an approved change/maintenance window or lacks matching change-control context; where telemetry permits, require corroborating device, configuration, or process-state effect. Suppress activity that fully matches approved maintenance, commissioning, failover, recovery, or tested control procedures. |