T1048.003 Exfiltration Over Unencrypted Non-C2 Protocol

T1048.003 Exfiltration Over Unencrypted Non-C2 Protocol

Sub-technique of: T1048

High-Level Description

Adversaries may steal data by exfiltrating it over an un-encrypted network protocol other 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.

Adversaries may opt to obfuscate this data, without the use of encryption, within network protocols that are natively unencrypted (such as HTTP, FTP, or DNS). This may include custom or publicly available encoding/compression algorithms (such as base64) as well as embedding data within protocol headers and fields.

Kill Chain Phase

• Exfiltration (TA0010)

Platforms: ESXi, Linux, macOS, Network Devices, Windows

What to Check

• Identify if Exfiltration Over Unencrypted Non-C2 Protocol technique is applicable to target environment
• Check ESXi systems for indicators of Exfiltration Over Unencrypted Non-C2 Protocol
• Check Linux systems for indicators of Exfiltration Over Unencrypted Non-C2 Protocol
• Check macOS systems for indicators of Exfiltration Over Unencrypted Non-C2 Protocol
• Verify mitigations are bypassed or absent (4 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 - HTTP

A firewall rule (ipfw,pf,iptables or firewalld) will be needed to allow exfiltration on port 1337.

Upon successful execution, sh will be used to make a directory (/tmp/victim-staging-area), write a txt file, and host the directory with Python on port 1337, to be later downloaded.

Supported Platforms: macos, linux

Atomic Test 2: Exfiltration Over Alternative Protocol - ICMP