Data Obfuscation: Protocol Impersonation

ID Name
T1001.001 Junk Data
T1001.002 Steganography
T1001.003 Protocol Impersonation

Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts. By impersonating legitimate protocols or web services, adversaries can make their command and control traffic blend in with legitimate network traffic.

Adversaries may impersonate a fake SSL/TLS handshake to make it look like subsequent traffic is SSL/TLS encrypted, potentially interfering with some security tooling, or to make the traffic look like it is related with a trusted entity.

ID: T1001.003
Sub-technique of:  T1001
Platforms: Linux, Windows, macOS
Version: 1.0
Created: 15 March 2020
Last Modified: 15 March 2020

Procedure Examples

ID Name Description

BADCALL uses a FakeTLS method during C2.[1]

S0239 Bankshot

Bankshot generates a false TLS handshake using a public certificate to disguise C2 network communications.[2]

C0017 C0017

During C0017, APT41 frequently configured the URL endpoints of their stealthy passive backdoor LOWKEY.PASSIVE to masquerade as normal web application traffic on an infected server.[3]

S0154 Cobalt Strike

Cobalt Strike can mimic the HTTP protocol for C2 communication, while hiding the actual data in either an HTTP header, URI parameter, the transaction body, or appending it to the URI.[4]

S0076 FakeM

FakeM C2 traffic attempts to evade detection by resembling data generated by legitimate messenger applications, such as MSN and Yahoo! messengers. Additionally, some variants of FakeM use modified SSL code for communications back to C2 servers, making SSL decryption ineffective.[5]


FALLCHILL uses fake Transport Layer Security (TLS) to communicate with its C2 server.[6]


FRAMESTING uses a cookie named DSID to mimic the name of a cookie used by Ivanti Connect Secure appliances for maintaining VPN sessions.[7]


HARDRAIN uses FakeTLS to communicate with its C2 server.[8]

G0126 Higaisa

Higaisa used a FakeTLS session for C2 communications.[9]

S0260 InvisiMole

InvisiMole can mimic HTTP protocol with custom HTTP "verbs" HIDE, ZVVP, and NOP.[10][11]

S0387 KeyBoy

KeyBoy uses custom SSL libraries to impersonate SSL in C2 traffic.[12]

G0032 Lazarus Group

Lazarus Group malware also uses a unique form of communication encryption known as FakeTLS that mimics TLS but uses a different encryption method, potentially evading SSL traffic inspection/decryption.[13][14][15][16]

S1100 Ninja

Ninja has the ability to mimic legitimate services with customized HTTP URL paths and headers to hide malicious traffic.[17]

S0439 Okrum

Okrum mimics HTTP protocol for C2 communication, while hiding the actual messages in the Cookie and Set-Cookie headers of the HTTP requests.[18]


SUNBURST masqueraded its network traffic as the Orion Improvement Program (OIP) protocol.[19]


TAINTEDSCRIBE has used FakeTLS for session authentication.[20]

S0022 Uroburos

Uroburos can use custom communication methodologies that ride over common protocols including TCP, UDP, HTTP, SMTP, and DNS in order to blend with normal network traffic. [21]


ID Mitigation Description
M1031 Network Intrusion Prevention

Network intrusion detection and prevention systems that use network signatures to identify traffic for specific adversary malware can be used to mitigate some obfuscation activity at the network level.


ID Data Source Data Component Detects
DS0029 Network Traffic Network Traffic Content

Monitor and analyze traffic patterns and packet inspection associated to protocol(s), leveraging SSL/TLS inspection for encrypted traffic, that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).