Data Obfuscation

Adversaries may obfuscate command and control traffic to make it more difficult to detect. Command and control (C2) communications are hidden (but not necessarily encrypted) in an attempt to make the content more difficult to discover or decipher and to make the communication less conspicuous and hide commands from being seen. This encompasses many methods, such as adding junk data to protocol traffic, using steganography, or impersonating legitimate protocols.

ID: T1001
Sub-techniques:  T1001.001, T1001.002, T1001.003
Tactic: Command And Control
Platforms: Linux, Windows, macOS
Data Sources: Network Traffic: Network Traffic Content
Requires Network:  Yes
Version: 1.1
Created: 31 May 2017
Last Modified: 15 March 2020

Procedure Examples

ID Name Description
G0001 Axiom

The Axiom group has used other forms of obfuscation, include commingling legitimate traffic with communications traffic so that network streams appear legitimate.

S0381 FlawedAmmyy

FlawedAmmyy may obfuscate portions of the initial C2 handshake.[1]

G0116 Operation Wocao

Operation Wocao has encrypted IP addresses used for "Agent" proxy hops with RC4.[2]

S0495 RDAT

RDAT has used encoded data within subdomains as AES ciphertext to communicate from the host to the C2.[3]

S0533 SLOTHFULMEDIA

SLOTHFULMEDIA has hashed a string containing system information prior to exfiltration via POST requests.[4]

Mitigations

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.

Detection

Analyze network data for uncommon data flows (e.g., a client sending significantly more data than it receives from a server). Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious. Analyze packet contents to detect communications that do not follow the expected protocol behavior for the port that is being used. [5]

References