# T1572 - Protocol Tunneling
## [Description from ATT&CK](https://attack.mitre.org/techniques/T1572)
<blockquote>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) 

[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 Impersonation](https://attack.mitre.org/techniques/T1001/003) to further conceal C2 communications and infrastructure. </blockquote>

## 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)


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## 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 }
```






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## 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}
```






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## 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}
```






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