t1090-002-external-proxy

name	T1090.002_external-proxy
description	Adversaries may use an external proxy to act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure.
category	configuration
version	18.1
author	cyberstrike-official
tags	["mitre-attack","enterprise","t1090.002","command-and-control","esxi","linux","network-devices","windows","macos","sub-technique"]
technique_id	T1090.002
tactic	command-and-control
all_tactics	["command-and-control"]
platforms	["ESXi","Linux","Network Devices","Windows","macOS"]
mitre_url	https://attack.mitre.org/techniques/T1090/002
tech_stack	["esxi","linux","network devices","windows","macos"]
cwe_ids	["CWE-300"]
chains_with	["T1090","T1090.001","T1090.003","T1090.004"]
prerequisites	["T1090"]
severity_boost	{"T1090":"Chain with T1090 for deeper attack path","T1090.001":"Chain with T1090.001 for deeper attack path","T1090.003":"Chain with T1090.003 for deeper attack path"}

T1090.002 External Proxy

Sub-technique of: T1090

High-Level Description

Adversaries may use an external proxy to act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap. Adversaries use these types of proxies to manage command and control communications, to provide resiliency in the face of connection loss, or to ride over existing trusted communications paths to avoid suspicion.

External connection proxies are used to mask the destination of C2 traffic and are typically implemented with port redirectors. Compromised systems outside of the victim environment may be used for these purposes, as well as purchased infrastructure such as cloud-based resources or virtual private servers. Proxies may be chosen based on the low likelihood that a connection to them from a compromised system would be investigated. Victim systems would communicate directly with the external proxy on the Internet and then the proxy would forward communications to the C2 server.

Kill Chain Phase

• Command and Control (TA0011)

Platforms: ESXi, Linux, Network Devices, Windows, macOS

What to Check

• Identify if External Proxy technique is applicable to target environment
• Check ESXi systems for indicators of External Proxy
• Check Linux systems for indicators of External Proxy
• Check Network Devices systems for indicators of External Proxy
• Verify mitigations are bypassed or absent (1 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Manual Testing

1. Identify Attack Surface: Determine if the target environment is susceptible to External Proxy by examining the target platforms (ESXi, Linux, Network Devices).

2. Assess Existing Defenses: Review whether mitigations for T1090.002 are in place. If defenses are absent or misconfigured, this technique may be exploitable.

3. Execute Test: Use tools and methods described in the MITRE ATT&CK page and external references below.