Application Layer Protocol

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

Adversaries may utilize many different protocols, including those used for web browsing, transferring files, electronic mail, or DNS.

ID: T1437
Sub-techniques:  T1437.001
Tactic Type: Post-Adversary Device Access
Platforms: Android, iOS
MTC ID: APP-29
Version: 1.2
Created: 25 October 2017
Last Modified: 24 October 2025

Procedure Examples

ID Name Description
S1083 Chameleon

Chameleon has used a SOCKS proxy.[1]

S1243 DCHSpy

DCHSpy has uploaded collected data to a Secure File Transfer Protocol (SFTP) server.[2]

S0550 DoubleAgent

DoubleAgent has used both FTP and TCP sockets for data exfiltration.[3]

S1054 Drinik

Drinik has code to use Firebase Cloud Messaging for receiving C2 instructions.[4]

C0054 Operation Triangulation

During Operation Triangulation, the threat actors used HTTPS POST requests for C2 communication.[5]

Mitigations

This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.

Detection Strategy

ID Name Analytic ID Analytic Description
DET0685 Detection of Application Layer Protocol AN1793

A defender observes an application establishing application-layer network sessions (e.g., HTTP(S), WebSocket, DNS, SMTP/IMAP) with destinations and request patterns that deviate from the enterprise baseline for that app category, especially when sessions occur during background execution or while the device is locked and exhibit beacon-like periodicity, anomalous SNI/Host patterns, or suspicious request/response size symmetry consistent with command polling and tasking over legitimate-looking protocols.

AN1794

A defender observes an application generating application-layer communications that blend with normal traffic (HTTP(S), WebSocket, DNS, mail protocols) but show deviations from enterprise baselines for that bundle ID—such as persistent background network sessions, regular low-volume polling intervals, anomalous SNI/Host destinations, uncommon DNS patterns, or uniform request/response sizing—suggesting command and control over legitimate-looking protocols without relying on tool signatures.

References