Detection of Multicast Discovery

Technique Detected:  Multicast Discovery | T0846.003

ID: DET0909
Domains: ICS
Analytics: AN2052, AN2163, AN2234, AN2285
Version: 1.0
Created: 22 April 2026
Last Modified: 13 October 2026

Analytics

AN2052

Real-time monitoring identifies Internet Group Management Protocol (IGMP) membership reports for Industrial Control System (ICS) multicast groups from a source not in the approved device inventory. OT operational-fidelity gate: Do not alert on novelty, scan/read volume, or enumeration alone. Alert when the source role is not authorized for discovery/polling and the target scope, address/tag range, protocol, or rate deviates from the established operational baseline. Suppress normal SCADA/HMI/historian polling, commissioning, asset inventory, backup, diagnostics, and approved engineering activity.

Log Sources
Data Component Name Channel
Network Traffic Flow (DC0078) networkdevice:snmp Internet Group Management Protocol (IGMP) membership report for Industrial Control Systems (ICS) multicast group from source not in approved device inventory
Mutable Elements
Field Description
ApprovedDeviceInventory MAC address inventory of devices authorized to subscribe to ICS multicast groups.

AN2163

Real-time monitoring identifies a Linux process joining Industrial Control System (ICS) multicast groups via socket() with IP_ADD_MEMBERSHIP, from a User Identifier (UID) not associated with any authorized ICS protection system monitoring application. OT operational-fidelity gate: Do not alert on novelty, scan/read volume, or enumeration alone. Alert when the source role is not authorized for discovery/polling and the target scope, address/tag range, protocol, or rate deviates from the established operational baseline. Suppress normal SCADA/HMI/historian polling, commissioning, asset inventory, backup, diagnostics, and approved engineering activity.

Log Sources
Data Component Name Channel
Network Connection Creation (DC0082) auditd:SYSCALL Linux Audit SYSCALL/EXECVE/SOCKADDR records (configured audit rule): socket/connect activity from a process outside the approved ICS monitoring-tool baseline to an ICS multicast destination/group
Mutable Elements
Field Description
ApprovedDeviceInventory MAC address inventory of devices authorized to subscribe to ICS multicast groups.

AN2234

Real-time monitoring identifies a new Internet Group Management Protocol (IGMP) group join or multicast subscription from a source Media Access Control (MAC)/Internet Protocol (IP) not in the approved device inventory, particularly for protection-relay Generic Object Oriented Substation Event (GOOSE) datasets. OT operational-fidelity gate: Do not alert on novelty, scan/read volume, or enumeration alone. Alert when the source role is not authorized for discovery/polling and the target scope, address/tag range, protocol, or rate deviates from the established operational baseline. Suppress normal SCADA/HMI/historian polling, commissioning, asset inventory, backup, diagnostics, and approved engineering activity.

Log Sources
Data Component Name Channel
Network Traffic Content (DC0085) NSM:Content Internet Group Management Protocol (IGMP) join or Generic Object Oriented Substation Event (GOOSE) multicast subscription from source Media Access Control (MAC) address not in approved device inventory
Mutable Elements
Field Description
ApprovedDeviceInventory MAC address inventory of devices authorized to subscribe to ICS multicast groups.

AN2285

Real-time monitoring identifies a Windows process joining Industrial Control System (ICS) multicast groups from a process not associated with an approved ICS protection relay monitoring tool. OT operational-fidelity gate: Do not alert on novelty, scan/read volume, or enumeration alone. Alert when the source role is not authorized for discovery/polling and the target scope, address/tag range, protocol, or rate deviates from the established operational baseline. Suppress normal SCADA/HMI/historian polling, commissioning, asset inventory, backup, diagnostics, and approved engineering activity.

Log Sources
Data Component Name Channel
Network Connection Creation (DC0082) WinEventLog:Sysmon EventCode=3 outbound connection from a process outside the approved ICS monitoring-tool baseline to an ICS multicast destination
Mutable Elements
Field Description
ApprovedDeviceInventory MAC address inventory of devices authorized to subscribe to ICS multicast groups.