Real-time monitoring identifies a field device entering firmware update mode and receiving a large data transfer on its firmware-capable protocol port from a source not in the approved engineering workstation list, followed by a device reboot, with post-reboot firmware hash not matching the authorized inventory. OT operational-fidelity gate: Alert only when the action is not attributable to an authorized operator/engineering source for the specific target and function, and it is either outside an approved change/maintenance window or lacks matching change-control context; where telemetry permits, require corroborating device, configuration, or process-state effect. Suppress activity that fully matches approved maintenance, commissioning, failover, recovery, or tested control procedures.
| Data Component | Name | Channel |
|---|---|---|
| Firmware Modification (DC0004) | assetinventory:FirmwareHash | reported firmware hash post-reboot not in authorized firmware inventory |
| Device Alarm (DC0108) | operationaldb:AlarmEvent | device reboot/restart alarm within firmware update window of the flagged transfer session |
| Network Traffic Content (DC0085) | NSM:Content | session on firmware-capable port exceeds session size threshold from source not in engineering workstation list outside change control window |
| Application Log Content (DC0038) | engineeringworkstation:ApplicationLog | firmware write session initiated without corresponding change ticket reference |
| Field | Description |
|---|---|
| AuthorizedFirmwareInventory | Cryptographic hash inventory of authorized firmware versions per device model. |
| AuthorizedFirmwareManagers | Accounts authorized to perform firmware update operations. |
| ChangeControlWindow | Scheduled maintenance periods during which firmware updates are authorized. |
| EngineeringWorkstationList | IP allowlist of workstations authorized to perform firmware updates. |
| FirmwareSessionSizeThreshold | Minimum byte count for a session to be considered a firmware transfer rather than routine configuration traffic, derived from known firmware image sizes. |
| FirmwareUpdateWindow | Time window within which a device reboot following a large session is considered part of the same firmware update event. |
| MaintenanceWindowSchedule | Recurring scheduled periods when firmware updates are expected to occur. |
Real-time monitoring identifies a firmware update utility on an Industrial Control System (ICS) Linux engineering host initiating a connection to a device Internet Protocol (IP) address on its firmware update port, by a User Identifier (UID) not in the approved firmware manager UIDs, outside a scheduled maintenance window. OT operational-fidelity gate: Alert only when the action is not attributable to an authorized operator/engineering source for the specific target and function, and it is either outside an approved change/maintenance window or lacks matching change-control context; where telemetry permits, require corroborating device, configuration, or process-state effect. Suppress activity that fully matches approved maintenance, commissioning, failover, recovery, or tested control procedures.
| Data Component | Name | Channel |
|---|---|---|
| Network Connection Creation (DC0082) | auditd:SYSCALL | Linux Audit SYSCALL/EXECVE/SOCKADDR records (configured audit rule): firmware updater connecting to device on firmware port, by User Identifier (UID) not in authorized firmware manager UIDs, outside maintenance window schedule |
| Field | Description |
|---|---|
| AuthorizedFirmwareInventory | Cryptographic hash inventory of authorized firmware versions per device model. |
| AuthorizedFirmwareManagers | Accounts authorized to perform firmware update operations. |
| ChangeControlWindow | Scheduled maintenance periods during which firmware updates are authorized. |
| EngineeringWorkstationList | IP allowlist of workstations authorized to perform firmware updates. |
| FirmwareSessionSizeThreshold | Minimum byte count for a session to be considered a firmware transfer rather than routine configuration traffic, derived from known firmware image sizes. |
| FirmwareUpdateWindow | Time window within which a device reboot following a large session is considered part of the same firmware update event. |
| MaintenanceWindowSchedule | Recurring scheduled periods when firmware updates are expected to occur. |
Real-time monitoring identifies vendor-specific firmware-update protocol traffic to ICS device IP addresses from a source not in the approved engineering-workstation or firmware-management baseline. OT operational-fidelity gate: Alert only when the action is not attributable to an authorized operator/engineering source for the specific target and function, and it is either outside an approved change/maintenance window or lacks matching change-control context; where telemetry permits, require corroborating device, configuration, or process-state effect. Suppress activity that fully matches approved maintenance, commissioning, failover, recovery, or tested control procedures.
| Data Component | Name | Channel |
|---|---|---|
| Network Traffic Flow (DC0078) | netflow:ipfix | IPFIX/NetFlow flow record (src/dst IP, src/dst port, protocol, packets/bytes/time): Trivial File Transfer Protocol (TFTP) session to device Internet Protocol (IP) address from source not in engineering workstation list followed by device reboot syslog within firmware transfer window |
| Field | Description |
|---|---|
| AuthorizedFirmwareInventory | Cryptographic hash inventory of authorized firmware versions per device model. |
| AuthorizedFirmwareManagers | Accounts authorized to perform firmware update operations. |
| ChangeControlWindow | Scheduled maintenance periods during which firmware updates are authorized. |
| EngineeringWorkstationList | IP allowlist of workstations authorized to perform firmware updates. |
| FirmwareSessionSizeThreshold | Minimum byte count for a session to be considered a firmware transfer rather than routine configuration traffic, derived from known firmware image sizes. |
| FirmwareUpdateWindow | Time window within which a device reboot following a large session is considered part of the same firmware update event. |
| MaintenanceWindowSchedule | Recurring scheduled periods when firmware updates are expected to occur. |
Real-time monitoring identifies a vendor firmware update utility executing outside a scheduled maintenance window or invoked by an account not in the approved firmware management role, immediately followed by a network session to a field device IP on its firmware protocol port. OT operational-fidelity gate: Alert only when the action is not attributable to an authorized operator/engineering source for the specific target and function, and it is either outside an approved change/maintenance window or lacks matching change-control context; where telemetry permits, require corroborating device, configuration, or process-state effect. Suppress activity that fully matches approved maintenance, commissioning, failover, recovery, or tested control procedures.
| Data Component | Name | Channel |
|---|---|---|
| Application Log Content (DC0038) | engineeringworkstation:ApplicationLog | firmware session initiated outside maintenance window schedule without change ticket reference |
| Process Creation (DC0032) | WinEventLog:Sysmon | EventCode=1 firmware-update utility spawned by an account outside the authorized firmware-management set or outside the approved maintenance window |
| Field | Description |
|---|---|
| AuthorizedFirmwareInventory | Cryptographic hash inventory of authorized firmware versions per device model. |
| AuthorizedFirmwareManagers | Accounts authorized to perform firmware update operations. |
| ChangeControlWindow | Scheduled maintenance periods during which firmware updates are authorized. |
| EngineeringWorkstationList | IP allowlist of workstations authorized to perform firmware updates. |
| FirmwareSessionSizeThreshold | Minimum byte count for a session to be considered a firmware transfer rather than routine configuration traffic, derived from known firmware image sizes. |
| FirmwareUpdateWindow | Time window within which a device reboot following a large session is considered part of the same firmware update event. |
| MaintenanceWindowSchedule | Recurring scheduled periods when firmware updates are expected to occur. |