t1071-003-mail-protocols

name	T1071.003_mail-protocols
description	Adversaries may communicate using application layer protocols associated with electronic mail delivery to avoid detection/network filtering by blending in with existing traffic.
category	configuration
version	18.1
author	cyberstrike-official
tags	["mitre-attack","enterprise","t1071.003","command-and-control","linux","macos","network-devices","windows","sub-technique"]
technique_id	T1071.003
tactic	command-and-control
all_tactics	["command-and-control"]
platforms	["Linux","macOS","Network Devices","Windows"]
mitre_url	https://attack.mitre.org/techniques/T1071/003
tech_stack	["linux","macos","network devices","windows"]
cwe_ids	["CWE-300"]
chains_with	["T1071","T1071.001","T1071.002","T1071.004","T1071.005"]
prerequisites	["T1071"]
severity_boost	{"T1071":"Chain with T1071 for deeper attack path","T1071.001":"Chain with T1071.001 for deeper attack path","T1071.002":"Chain with T1071.002 for deeper attack path"}

T1071.003 Mail Protocols

Sub-technique of: T1071

High-Level Description

Adversaries may communicate using application layer protocols associated with electronic mail delivery to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.

Protocols such as SMTP/S, POP3/S, and IMAP that carry electronic mail may be very common in environments. Packets produced from these protocols may have many fields and headers in which data can be concealed. Data could also be concealed within the email messages themselves. An adversary may abuse these protocols to communicate with systems under their control within a victim network while also mimicking normal, expected traffic.

Kill Chain Phase

• Command and Control (TA0011)

Platforms: Linux, macOS, Network Devices, Windows

What to Check

• Identify if Mail Protocols technique is applicable to target environment
• Check Linux systems for indicators of Mail Protocols
• Check macOS systems for indicators of Mail Protocols
• Check Network Devices systems for indicators of Mail Protocols
• Verify mitigations are bypassed or absent (2 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Manual Testing

1. Identify Attack Surface: Determine if the target environment is susceptible to Mail Protocols by examining the target platforms (Linux, macOS, Network Devices).

2. Assess Existing Defenses: Review whether mitigations for T1071.003 are in place. If defenses are absent or misconfigured, this technique may be exploitable.

3. Execute Test: Use tools and methods described in the MITRE ATT&CK page and external references below.

Note: No Atomic Red Team tests available for this technique. See Atomic Red Team GitHub for updates.

Remediation Guide

M1037 Filter Network Traffic