The adversary is trying to manipulate, disable, or damage physical control processes. Impair Process Control consists of techniques that adversaries use to disrupt control logic and cause determinantal effects to processes being controlled in the target environment. Targets of interest may include active procedures or parameters that manipulate the physical environment. These techniques can also include prevention or manipulation of reporting elements and control logic. If an adversary has modified process functionality, then they may also obfuscate the results, which are often self-revealing in their impact on the outcome of a product or the environment. The direct physical control these techniques exert may also threaten the safety of operators and downstream users, which can prompt response mechanisms. Adversaries may follow up with or use [Inhibit Response Function](https://attack.mitre.org/tactics/TA0107) techniques in tandem, to assist with the successful abuse of control processes to result in [Impact](https://attack.mitre.org/tactics/TA0105).

Subissues

Issuelinks
Modify Parameter 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](https://attack.mitre.org/tactics/TA0105) 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.
Modify Firmware Firmware is low-level software embedded in hardware that enables systems and devices to function properly and is commonly found in ICS environments. Adversaries may modify firmware on a system or device by installing malicious or vulnerable versions that enable them to achieve objectives such as [Persistence](https://attack.mitre.org/tactics/TA0110), [Impair Process Control](https://attack.mitre.org/tactics/TA0106), and [Inhibit Response Function](https://attack.mitre.org/tactics/TA0107). Adversaries may modify system and device firmware by using the built-in firmware update functionality which may support local or remote installation. The malicious or vulnerable firmware may be delivered via [Replication Through Removable Media](https://attack.mitre.org/techniques/T0847), [Supply Chain Compromise](https://attack.mitre.org/techniques/T0862), or [Remote Services](https://attack.mitre.org/techniques/T0886). Once installed, the malicious or vulnerable firmware could be used to provide [Rootkit](https://attack.mitre.org/techniques/T0851) and [Hooking](https://attack.mitre.org/techniques/T0874) functionality, [Exploitation for Privilege Escalation](https://attack.mitre.org/techniques/T0890), or [Denial of Service](https://attack.mitre.org/techniques/T0814).(Citation: Basnight, Zachry, et al.)
Brute Force I/O Adversaries may repetitively or successively change I/O point values to perform an action. Brute Force I/O may be achieved by changing either a range of I/O point values or a single point value repeatedly to manipulate a process function. The adversary's goal and the information they have about the target environment will influence which of the options they choose. In the case of brute forcing a range of point values, the adversary may be able to achieve an impact without targeting a specific point. In the case where a single point is targeted, the adversary may be able to generate instability on the process function associated with that particular point. Adversaries may use Brute Force I/O to cause failures within various industrial processes. These failures could be the result of wear on equipment or damage to downstream equipment.
Change Program State Adversaries may attempt to change the state of the current program on a control device. Program state changes may be used to allow for another program to take over control or be loaded onto the device.
Modify Control Logic Adversaries may place malicious code in a system, which can cause the system to malfunction by modifying its control logic. Control system devices use programming languages (e.g. relay ladder logic) to control physical processes by affecting actuators, which cause machines to operate, based on environment sensor readings. These devices often include the ability to perform remote control logic updates. Program code is normally edited in a vendor-specific Integrated Development Environment (IDE) that relies on proprietary tools and features. These IDEs allow an engineer to perform host target development and may have the ability to run the code on the machine it is programmed for. The IDE will transmit the control logic to the testing device, and will perform the required device-specific functions to apply the changes and make them active. An adversary may attempt to use this host target IDE to modify device control logic. Even though proprietary tools are often used to edit and update control logic, the process can usually be reverse-engineered and reproduced with open-source tools. An adversary can de-calibrate a sensor by removing functions in control logic that account for sensor error. This can be used to change a control process without actually spoofing command messages to a controller or device. It is believed this process happened in the lesser known over-pressurizer attacks build into Stuxnet. Pressure sensors are not perfect at translating pressure into an analog output signal, but their errors can be corrected by calibration. The pressure controller can be told what the “real” pressure is for given analog signals and then automatically linearize the measurement to what would be the “real” pressure. If the linearization is overwritten by malicious code on the S7-417 controller, analog pressure readings will be “corrected” during the attack by the pressure controller, which then interprets all analog pressure readings as perfectly normal pressure no matter how high or low their analog values are. The pressure controller then acts accordingly by never opening the stage exhaust valves. In the meantime, actual pressure keeps rising. (Citation: Stuxnet - Langner - 201311) In the Maroochy Attack, Vitek Boden 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 by Hunter Watertech for its use in changing configurations in the PDS computers. This ultimately led to 800,000 liters of raw sewage being spilled out into the community. (Citation: Maroochy - MITRE - 200808)
Unauthorized Message Adversaries may send unauthorized messages to ICS systems and devices to evade defenses or manipulate processes. Unauthorized messages can be categorized as either reporting messages that contain telemetry data about the current state of systems, devices, and processes or as command messages which instruct systems and devices on how to operate. By injecting unauthorized messages, adversaries can make it appear as if everything is working correctly when it isn’t, trigger alarms to misdirect personnel or impact processes, and manipulate controls to disrupt processes.(Citation: Bonnie Zhu, Anthony Joseph, Shankar Sastry 2011) Adversaries may send unauthorized messages in an ICS environment using software found within the environment (living-off-the-land, vendor-specific interfaces, etc.), custom tooling leveraging OT protocols and libraries, or by positioning themselves between systems and devices and injecting messages into the communications such as the case with an [Adversary-in-the-Middle](https://attack.mitre.org/techniques/T0830) attack.

Linked Issues

Issuelinks
is related to Tactics
is part of ICS ATT&CK
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