Modify Controller Tasking Technique ID T0821 Tactic Execution Data Sources File : File Modification Asset : Software/Firmware Asset Field Controller/RTU/PLC/IED. Adversaries may modify the tasking of a controller to allow for the execution of their own programs. Modification of controller tasking can be accomplished using a Program Download in addition to other types of program modification such as online edit and program append. An adversary may associate their program with tasks that have a higher priority or execute associated programs more frequently. For instance, an adversary may add their program to the task, Organization Block 1 (OB1)”]
Source: https://collaborate.mitre.org/attackics/index.php/Technique/T0821