Modify Program
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 or add a program on a controller to affect how it interacts with the physical process, peripheral devices and other hosts on the network. Modification to controller programs can be accomplished using a Program Download in addition to other types of program modification such as online edit and program append. Program modification encompasses the addition and modification of instructions and logic contained in Program Organization Units (POU) and similar programming elements found on controllers. This can include, for example, adding new functions to a controller, modifying the logic in existing functions and making new calls from one function to another. Some programs may allow an adversary to interact directly with the native API of the controller to take advantage of obscure features or vulnerabilities.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN1915
Monitor device management protocols for functions that modify programs such as online edit and program append events. Monitor device alarms that indicate the program has changed, although not all devices produce such alarms. Engineering and asset management software will often maintain a copy of the expected program loaded on a controller and may also record any changes made to controller programs. Data from these platforms can be used to identify modified controller programs. Monitor device application logs that indicate the program has changed, although not all devices produce such logs.
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.