t1572-protocol-tunneling

name	T1572_protocol-tunneling
description	Adversaries may tunnel network communications to and from a victim system within a separate protocol to avoid detection/network filtering and/or enable access to otherwise unreachable systems.
category	configuration
version	18.1
author	cyberstrike-official
tags	["mitre-attack","enterprise","t1572","command-and-control","esxi","linux","macos","windows"]
technique_id	T1572
tactic	command-and-control
all_tactics	["command-and-control"]
platforms	["ESXi","Linux","macOS","Windows"]
mitre_url	https://attack.mitre.org/techniques/T1572
tech_stack	["esxi","linux","macos","windows"]
cwe_ids	["CWE-300"]
chains_with	[]
prerequisites	[]
severity_boost	{}

T1572 Protocol Tunneling

High-Level Description

Adversaries may tunnel network communications to and from a victim system within a separate protocol to avoid detection/network filtering and/or enable access to otherwise unreachable systems. Tunneling involves explicitly encapsulating a protocol within another. This behavior may conceal malicious traffic by blending in with existing traffic and/or provide an outer layer of encryption (similar to a VPN). Tunneling could also enable routing of network packets that would otherwise not reach their intended destination, such as SMB, RDP, or other traffic that would be filtered by network appliances or not routed over the Internet.

There are various means to encapsulate a protocol within another protocol. For example, adversaries may perform SSH tunneling (also known as SSH port forwarding), which involves forwarding arbitrary data over an encrypted SSH tunnel.

Protocol Tunneling may also be abused by adversaries during Dynamic Resolution. Known as DNS over HTTPS (DoH), queries to resolve C2 infrastructure may be encapsulated within encrypted HTTPS packets.

Adversaries may also leverage Protocol Tunneling in conjunction with Proxy and/or Protocol or Service Impersonation to further conceal C2 communications and infrastructure.

Kill Chain Phase

• Command and Control (TA0011)

Platforms: ESXi, Linux, macOS, Windows

What to Check

• Identify if Protocol Tunneling technique is applicable to target environment
• Check ESXi systems for indicators of Protocol Tunneling
• Check Linux systems for indicators of Protocol Tunneling
• Check macOS systems for indicators of Protocol Tunneling
• Verify mitigations are bypassed or absent (2 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Atomic Red Team Tests

The following tests are from Atomic Red Team and provide actionable ways to test this technique:

Atomic Test 1: DNS over HTTPS Large Query Volume

This test simulates an infected host sending a large volume of DoH queries to a command and control server. The intent of this test is to trigger threshold based detection on the number of DoH queries either from a single source system or to a single targe domain. A custom domain and sub-domain will need to be passed as input parameters for this test to work. Upon execution, DNS information about the domain will be displayed for each callout in a JSON format.