Remote System Discovery: Port Scan

Adversaries may perform a port scan on a system, device, or network to identify live hosts, enumerate open ports and running services, identify operating systems, and map out the network.[1] The results of a port scan may inform adversary Discovery, Lateral Movement, and vulnerability exploitation decisions (Exploitation for Evasion, Exploitation for Privilege Escalation, Exploitation of Remote Services).

Some common tools for executing a port scan include nmap, netcat, and the Advanced Port Scanner.

ID: T0846.001
Sub-technique of:  T0846
Tactic: Discovery
Version: 1.0
Created: 20 April 2026
Last Modified: 23 April 2026

Procedure Examples

ID Name Description
C0063 2025 Poland Wiper Attacks

During the 2025 Poland Wiper Attacks, the adversaries used Advanced Port Scanner and Advanced IP Scanner to conduct remote system discovery activities.[2]

S1045 INCONTROLLER

INCONTROLLER has the ability to perform scans for TCP port 4840 to identify devices running OPC UA servers.[3]

S0604 Industroyer

The Industroyer IEC 61850 payload component has the ability to discover relevant devices in the infected host's network subnet by attempting to connect on port 102.[4]

S1006 PLC-Blaster

PLC-Blaster scans the network to find other Siemens S7 PLC devices to infect. It locates these devices by checking for a service listening on TCP port 102.[5]

Targeted Assets

ID Asset
A0008 Application Server
A0007 Control Server
A0009 Data Gateway
A0006 Data Historian
A0017 Distributed Control System (DCS) Controller
A0016 Firewall
A0002 Human-Machine Interface (HMI)
A0005 Intelligent Electronic Device (IED)
A0012 Jump Host
A0018 Programmable Automation Controller (PAC)
A0003 Programmable Logic Controller (PLC)
A0004 Remote Terminal Unit (RTU)
A0014 Routers
A0010 Safety Controller
A0015 Switch
A0011 Virtual Private Network (VPN) Server
A0001 Workstation

Mitigations

ID Mitigation Description
M0931 Network Intrusion Prevention

Use network intrusion detection/prevention systems to detect and prevent port scans.

M0930 Network Segmentation

Ensure proper network segmentation is followed to protect critical systems and devices.

M0814 Static Network Configuration

ICS environments typically have more statically defined devices, therefore minimize the use of both IT discovery protocols (e.g., DHCP, LLDP) and discovery functions in automation protocols.[6][7] Examples of automation protocols with discovery capabilities include OPC UA Device Discovery[8], BACnet[9], and Ethernet/IP.[10]

Detection Strategy

ID Name Analytic ID Analytic Description
DET0907 Detection of Port Scan AN2050

Monitor for new processes engaging in scanning activity or connecting to multiple systems by correlating process creation network data.

Monitor for hosts enumerating network connected resources using non-ICS enterprise protocols.

References