Block Communications
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
Operational technology communications occur over serial COM, Ethernet, Wi-Fi, cellular (4G/5G), and satellite mediums. Adversaries may block communications to prevent reporting messages and command messages from reaching their intended target devices disrupting processes, operations, and causing cyber-physical impacts. Adversaries may block communications by either making modifications to software (System Firmware, Module Firmware, Hooking, and Rootkit) and services (Service Stop, Denial of Service) on systems and devices or by positioning themselves between systems and devices and intercepting and blocking the communications such as the case with an Adversary-in-the-Middle attack.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN2053
Monitor asset alarms which may help identify a loss of communications. Consider correlating alarms with other data sources that indicate traffic has been blocked, such as network traffic. In cases where alternative methods of communicating with outstations exist, alarms may still be visible even if messages are blocked. Monitor for a loss of network communications, which may indicate this technique is being used. Monitor for lack of operational process data which may help identify a loss of communications. This will not directly detect the technique’s execution but instead may provide additional evidence that the technique has been used and may complement other detections. […]
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.