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Internal Proxy (T1090.001) is a MITRE ATT&CK technique associated with Command and Control . Adversaries may use an internal proxy to direct command and control traffic between two or more systems in a compromised environment.
Internal Proxy (T1090.001) is a MITRE ATT&CK technique associated with Command and Control. Adversaries may use an internal proxy to direct command and control traffic between two or more systems in a compromised environment.
Attackers use Internal Proxy because it provides a reliable way to advance their objective within the Command and Control tactic, often with a favorable balance of impact versus detectability on ESXi, 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 use an internal proxy to direct command and control traffic between two or more systems in a compromised environment. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap. (Citation: Trend Micro APT Attack Tools) Adversaries use internal proxies to manage command and control communications inside a compromised environment, to reduce the number of simultaneous outbound network connections, to provide resiliency in the face of connection loss, or to ride over existing trusted communications paths between infected systems to avoid suspicion. Internal proxy connections may use common peer-to-peer (p2p) networking protocols, such as SMB, to better blend in with the environment.
By using a compromised internal system as a proxy, adversaries may conceal the true destination of C2 traffic while reducing the need for numerous connections to external systems.
No universal command represents Internal Proxy. 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.