Replication Through Removable Media
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 move onto systems, such as those separated from the enterprise network, by copying malware to removable media which is inserted into the control systems environment. The adversary may rely on unknowing trusted third parties, such as suppliers or contractors with access privileges, to introduce the removable media. This technique enables initial access to target devices that never connect to untrusted networks, but are physically accessible. Operators of the German nuclear power plant, Gundremmingen, discovered malware on a facility computer not connected to the internet. The malware included Conficker and W32.Ramnit, which were also found on eighteen removable disk drives in the facility. The plant has since checked for infection and cleaned up more than 1,000 computers. An ESET researcher commented that internet disconnection does not guarantee system safety from infection or payload execution.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN1866
Monitor for newly executed processes that execute from removable media after it is mounted or when initiated by a user. If a remote access tool is used in this manner to move laterally, then additional actions are likely to occur after execution, such as opening network connections for Command and Control and system and network information Discovery. Monitor for newly constructed files copied to or from removable media. Monitor for newly constructed drive letters or mount points to removable media. Monitor for files accessed on removable media, particularly those with executable content.
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.