Real-time monitoring identifies an Industrial Control System (ICS) host or server establishing outbound connections on a commonly-allowed port (e.g., 443, 80, 8080, 53, etc.) to a destination not in the approved vendor/business domain list, where that host's documented network role does not require external connectivity. Documented real-world use: Sandworm's 2015 Ukraine power grid attack used port 443 for Command and Control (C2) communications. OT operational-fidelity gate: Alert only when the asset's documented role does not permit the connection and the destination/proxy/service is outside the approved communications profile, with process/service identity used as corroboration where available. Suppress approved vendor support, update repositories, remote operations, failover paths, and documented temporary connectivity. SNI and certificate attributes are TLS/session metadata; do not treat them as decrypted payload content. Encrypted application content requires a separate inspection point.
| Data Component | Name | Channel |
|---|---|---|
| Network Traffic Flow (DC0078) | netflow:ipfix | IPFIX/NetFlow flow record (src/dst IP, src/dst port, protocol, packets/bytes/time): egress flow on port 443/80/8080/53 from Industrial Control Systems (ICS) host in no-external-connectivity role list to destination not in approved vendor domains |
| Network Traffic Content (DC0085) | zeek:ssl | Transport Layer Security (TLS) Server Name Indication (SNI) or certificate issuer does not match approved vendor domains or recognized Content Delivery Network (CDN) serving vendor content |
| Field | Description |
|---|---|
| ApprovedVendorDomains | Allowlist of legitimate vendor domains for software updates, licensing, or remote support. |
| NoExternalConnectivityRoleList | Inventory of ICS hosts whose documented function never requires outbound internet connectivity. |
Real-time monitoring identifies an Industrial Control System (ICS) Linux service process initiating an outbound connection on a commonly-used port to a destination not in the approved vendor domain list. OT operational-fidelity gate: Alert only when the asset's documented role does not permit the connection and the destination/proxy/service is outside the approved communications profile, with process/service identity used as corroboration where available. Suppress approved vendor support, update repositories, remote operations, failover paths, and documented temporary connectivity.
| Data Component | Name | Channel |
|---|---|---|
| Network Connection Creation (DC0082) | auditd:SYSCALL | Linux Audit SYSCALL/EXECVE/SOCKADDR records (configured audit rule): connect() syscall on port (e.g., 80, 443, 8080, etc.) to destination not in approved vendor domains, from Industrial Control Systems (ICS) service process |
| Field | Description |
|---|---|
| ApprovedVendorDomains | Allowlist of legitimate vendor domains for software updates, licensing, or remote support. |
| NoExternalConnectivityRoleList | Inventory of ICS hosts whose documented function never requires outbound internet connectivity. |
Real-time monitoring identifies an embedded field device initiating outbound connections on a commonly-used port to a destination outside the device's documented operational communication profile, which for most embedded Industrial Control System (ICS) devices normally should not include arbitrary outbound internet connectivity under the approved communications architecture. OT operational-fidelity gate: Alert only when the asset's documented role does not permit the connection and the destination/proxy/service is outside the approved communications profile, with process/service identity used as corroboration where available. Suppress approved vendor support, update repositories, remote operations, failover paths, and documented temporary connectivity.
| Data Component | Name | Channel |
|---|---|---|
| Network Traffic Flow (DC0078) | NSM:Connections | embedded device_ip initiates outbound connection on port 443/80/8080 to destination outside documented operational profile |
| Field | Description |
|---|---|
| ApprovedVendorDomains | Allowlist of legitimate vendor domains for software updates, licensing, or remote support. |
| NoExternalConnectivityRoleList | Inventory of ICS hosts whose documented function never requires outbound internet connectivity. |
Real-time monitoring identifies an Industrial Control System (ICS) vendor process making outbound connections on commonly-allowed port (e.g., 80, 443, 8080, etc.) to a destination not in the approved vendor domain list, from a host whose documented role does not require external connectivity. OT operational-fidelity gate: Alert only when the asset's documented role does not permit the connection and the destination/proxy/service is outside the approved communications profile, with process/service identity used as corroboration where available. Suppress approved vendor support, update repositories, remote operations, failover paths, and documented temporary connectivity.
| Data Component | Name | Channel |
|---|---|---|
| Network Connection Creation (DC0082) | WinEventLog:Sysmon | EventCode=3 on port 80/443/8080 from process not matching Industrial Control Systems (ICS) vendor update process allowlist |
| Field | Description |
|---|---|
| ApprovedVendorDomains | Allowlist of legitimate vendor domains for software updates, licensing, or remote support. |
| NoExternalConnectivityRoleList | Inventory of ICS hosts whose documented function never requires outbound internet connectivity. |