T1048 Exfiltration Over Alternative Protocol

T1048 Exfiltration Over Alternative Protocol

High-Level Description

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 can be done using various common operating system utilities such as Net/SMB or FTP. On macOS and Linux curl may be used to invoke protocols such as HTTP/S or FTP/S to exfiltrate data from a system.

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.

Kill Chain Phase

• Exfiltration (TA0010)

Platforms: ESXi, IaaS, Linux, macOS, Network Devices, Office Suite, SaaS, Windows

What to Check

• Identify if Exfiltration Over Alternative Protocol technique is applicable to target environment
• Check ESXi systems for indicators of Exfiltration Over Alternative Protocol
• Check IaaS systems for indicators of Exfiltration Over Alternative Protocol
• Check Linux systems for indicators of Exfiltration Over Alternative Protocol
• Verify mitigations are bypassed or absent (6 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: 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.