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System Network Connections Discovery (T1049) is a MITRE ATT&CK technique associated with Discovery . Adversaries may attempt to get a listing of network connections to or from the compromised system they are currently accessing or from remote systems by querying for informatio…
System Network Connections Discovery (T1049) is a MITRE ATT&CK technique associated with Discovery. Adversaries may attempt to get a listing of network connections to or from the compromised system they are currently accessing or from remote systems by querying for information over the network.
Attackers use System Network Connections Discovery because it provides a reliable way to advance their objective within the Discovery tactic, often with a favorable balance of impact versus detectability on ESXi, IaaS, Linux, macOS, Network Devices, Windows environments. Defenders should assess this behavior in the context of the affected platform and adjacent activity rather than treating it as a standalone indicator.
Adversaries may attempt to get a listing of network connections to or from the compromised system they are currently accessing or from remote systems by querying for information over the network.
An adversary who gains access to a system that is part of a cloud-based environment may map out Virtual Private Clouds or Virtual Networks in order to determine what systems and services are connected. The actions performed are likely the same types of discovery techniques depending on the operating system, but the resulting information may include details about the networked cloud environment relevant to the adversary's goals. Cloud providers may have different ways in which their virtual networks operate.(Citation: Amazon AWS VPC Guide)(Citation: Microsoft Azure Virtual Network Overview)(Citation: Google VPC Overview) Similarly, adversaries who gain access to network devices may also perform similar discovery activities to gather information about connected systems and services.
Utilities and commands that acquire this information include netstat, "net use," and "net session" with Net. In Mac and Linux, netstat and <code>lsof</code> can be used to list current connections. <code>who -a</code> and <code>w</code> can be used to show which users are currently logged in, similar to "net session". Additionally, built-in features native to network devices and Network Device CLI may be used (e.g. <code>show ip sockets</code>, <code>show tcp brief</code>).(Citation: US-CERT-TA18-106A) On ESXi servers, the command esxi network ip connection list can be used to list active network connections.(Citation: Sygnia ESXi Ransomware 2025)
No universal command represents System Network Connections Discovery. Capture the exact command line, arguments, parent process, account, host, and execution time from the investigated environment; do not operationalize unverified examples.
| Event ID | Log Channel | What It Indicates |
|---|---|---|
| Environment-specific | Relevant Windows channel(s) | Correlate authentication, process, object-access, and configuration events with the observed execution context. |
| Sysmon Event ID | Name | Why It's Relevant Here |
|---|---|---|
| Environment-specific | Validate configured telemetry | Use process, network, file, registry, DNS, or image-load telemetry only when relevant and enabled. |
No MITRE detection guidance published for this technique.
Relevant ATT&CK Data Sources: N/A
A universal Sigma rule would create unreliable results because this technique has no single guaranteed observable. Build detection logic from a documented behavior and supported data source, scope it to the affected platform, and validate it against benign administrative activity before deployment.
Start with the data sources named in the detection section. Scope searches by asset, identity, and time window; correlate the primary behavior with preceding access and subsequent actions. A portable query is intentionally not provided where the technique lacks a universal schema or observable.
No MITRE mitigations mapped to this technique.