Rootkit
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 deploy rootkits to hide the presence of programs, files, network connections, services, drivers, and other system components. Rootkits are programs that hide the existence of malware by intercepting and modifying operating-system API calls that supply system information. Rootkits or rootkit-enabling functionality may reside at the user or kernel level in the operating system, or lower. Firmware rootkits that affect the operating system yield nearly full control of the system. While firmware rootkits are normally developed for the main processing board, they can also be developed for the I/O that is attached to an asset. Compromise of this firmware allows the modification of all of the process variables and functions the module engages in. This may result in commands being disregarded and false information being fed to the main device. By tampering with device processes, an adversary may inhibit its expected response functions and possibly enable Impact.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN1912
Monitor for changes made to firmware for unexpected modifications to settings and/or data that may be used by rootkits to hide the presence of programs, files, network connections, services, drivers, and other system components. Asset management systems should be consulted to understand known-good firmware versions and configurations.
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.