Exfiltration Over C2 Channel

Adversaries may steal data by exfiltrating it over an existing command and control channel. Stolen data is encoded into the normal communications channel using the same protocol as command and control communications.

ID: T1041
Sub-techniques:  No sub-techniques
Tactic: Exfiltration
Platforms: Linux, Windows, macOS
Data Sources: Command: Command Execution, File: File Access, Network Traffic: Network Connection Creation, Network Traffic: Network Traffic Content, Network Traffic: Network Traffic Flow
Requires Network:  Yes
Version: 2.0
Created: 31 May 2017
Last Modified: 12 March 2020

Procedure Examples

ID Name Description
S0045 ADVSTORESHELL

ADVSTORESHELL exfiltrates data over the same channel used for C2.[1]

S0584 AppleJeus

AppleJeus has exfiltrated collected host information to a C2 server.[2]

G0022 APT3

APT3 has a tool that exfiltrates data over the C2 channel.[3]

G0050 APT32

APT32's backdoor has exfiltrated data using the already opened channel with its C&C server.[4]

G0087 APT39

APT39 has exfiltrated stolen victim data through C2 communications.[5]

S0373 Astaroth

Astaroth exfiltrates collected information from its r1.log file to the external C2 server. [6]

S0438 Attor

Attor has exfiltrated data over the C2 channel.[7]

S0031 BACKSPACE

Adversaries can direct BACKSPACE to upload files to the C2 Server.[8]

S0239 Bankshot

Bankshot exfiltrates data over its C2 channel.[9]

S0520 BLINDINGCAN

BLINDINGCAN has sent user and system information to a C2 server via HTTP POST requests.[10][11]

S0077 CallMe

CallMe exfiltrates data to its C2 server over the same protocol as C2 communications.[12]

S0351 Cannon

Cannon exfiltrates collected data over email via SMTP/S and POP3/S C2 channels.[13]

S0484 Carberp

Carberp has exfiltrated data via HTTP to already established C2 servers.[14][15]

S0572 Caterpillar WebShell

Caterpillar WebShell can upload files over the C2 channel.[16]

G0114 Chimera

Chimera has used Cobalt Strike C2 beacons for data exfiltration.[17]

S0538 Crutch

Crutch can exfiltrate data over the primary C2 channel (Dropbox HTTP API).[18]

S0600 Doki

Doki has used Ngrok to establish C2 and exfiltrate data.[19]

S0502 Drovorub

Drovorub can exfiltrate files over C2 infrastructure.[20]

S0062 DustySky

DustySky has exfiltrated data to the C2 server.[21]

S0024 Dyre

Dyre has the ability to send information staged on a compromised host externally to C2.[22]

S0377 Ebury

Ebury can exfiltrate SSH credentials through custom DNS queries.[23]

S0367 Emotet

Emotet has been seen exfiltrating system information stored within cookies sent within an HTTP GET request back to its C2 servers. [24]

S0363 Empire

Empire can send data gathered from a target through the command and control channel.[25]

S0568 EVILNUM

EVILNUM can upload files over the C2 channel from the infected host.[26]

G0101 Frankenstein

Frankenstein has collected information via Empire, which is automatically sent the data back to the adversary's C2.[27]

G0093 GALLIUM

GALLIUM used Web shells and HTRAN for C2 and to exfiltrate data.[28]

G0047 Gamaredon Group

A Gamaredon Group file stealer can transfer collected files to a hardcoded C2 server.[29]

S0493 GoldenSpy

GoldenSpy has exfiltrated host environment information to an external C2 domain via port 9006.[30]

S0588 GoldMax

GoldMax can exfiltrate files over the existing C2 channel.[31][32]

S0477 Goopy

Goopy has the ability to exfiltrate data over the Microsoft Outlook C2 channel.[33]

S0531 Grandoreiro

Grandoreiro can send data it retrieves to the C2 server.[34]

S0391 HAWKBALL

HAWKBALL has sent system information and files over the C2 channel.[35]

G0126 Higaisa

Higaisa exfiltrated data over its C2 channel.[36]

S0376 HOPLIGHT

HOPLIGHT has used its C2 channel to exfiltrate data.[37]

S0431 HotCroissant

HotCroissant has the ability to download files from the infected host to the command and control (C2) server.[38]

S0434 Imminent Monitor

Imminent Monitor has uploaded a file containing debugger logs, network information and system information to the C2.[39]

G0004 Ke3chang

Ke3chang transferred compressed and encrypted RAR files containing exfiltration through the established backdoor command and control channel during operations.[40]

S0487 Kessel

Kessel has exfiltrated information gathered from the infected system to the C2 server.[41]

S0526 KGH_SPY

KGH_SPY can exfiltrate collected information from the host to the C2 server.[42]

G0094 Kimsuky

Kimsuky has exfiltrated data over its email C2 channel.[43]

G0032 Lazarus Group

Lazarus Group malware IndiaIndia saves information gathered about the victim to a file that is uploaded to one of its 10 C2 servers. Another Lazarus Group malware sample also performs exfiltration over the C2 channel.[44][45][46]

S0395 LightNeuron

LightNeuron exfiltrates data over its email C2 channel.[47]

S0447 Lokibot

Lokibot has the ability to initiate contact with command and control (C2) to exfiltrate stolen data.[48]

S0409 Machete

Machete's collected data is exfiltrated over the same channel used for C2.[49]

S0459 MechaFlounder

MechaFlounder has the ability to send the compromised user's account name and hostname within a URL to C2.[50]

S0079 MobileOrder

MobileOrder exfiltrates data to its C2 server over the same protocol as C2 communications.[12]

G0069 MuddyWater

MuddyWater has used C2 infrastructure to receive exfiltrated data.[51]

S0034 NETEAGLE

NETEAGLE is capable of reading files over the C2 channel.[8]

S0385 njRAT

njRAT has used HTTP to receive stolen information from the infected machine.[52]

S0439 Okrum

Data exfiltration is done by Okrum using the already opened channel with the C2 server.[53]

S0264 OopsIE

OopsIE can upload files from the victim's machine to its C2 server.[54]

G0116 Operation Wocao

Operation Wocao has used the Xserver backdoor to exfiltrate data.[55]

S0587 Penquin

Penquin can execute the command code do_upload to send files to C2.[56]

S0428 PoetRAT

PoetRAT has exfiltrated data over the C2 channel.[57]

S0441 PowerShower

PowerShower has used a PowerShell document stealer module to pack and exfiltrate .txt, .pdf, .xls or .doc files smaller than 5MB that were modified during the past two days.[58]

S0238 Proxysvc

Proxysvc performs data exfiltration over the control server channel using a custom protocol.[59]

S0078 Psylo

Psylo exfiltrates data to its C2 server over the same protocol as C2 communications.[12]

S0147 Pteranodon

Pteranodon exfiltrates screenshot files to its C2 server.[29]

S0192 Pupy

Pupy can send screenshots files, keylogger data, files, and recorded audio back to the C2 server.[60]

S0495 RDAT

RDAT can exfiltrate data gathered from the infected system via the established Exchange Web Services API C2 channel.[61]

S0375 Remexi

Remexi performs exfiltration over BITSAdmin, which is also used for the C2 channel.[62]

S0496 REvil

REvil can exfiltrate host and malware information to C2 servers.[63]

S0448 Rising Sun

Rising Sun can send data gathered from the infected machine via HTTP POST request to the C2.[64]

S0240 ROKRAT

ROKRAT sends collected files back over same C2 channel.[65]

G0034 Sandworm Team

Sandworm Team has sent system information to its C2 server using HTTP.[66]

S0445 ShimRatReporter

ShimRatReporter sent generated reports to the C2 via HTTP POST requests.[67]

S0533 SLOTHFULMEDIA

SLOTHFULMEDIA has sent system information to a C2 server via HTTP and HTTPS POST requests.[68]

S0543 Spark

Spark has exfiltrated data over the C2 channel.[69]

G0038 Stealth Falcon

After data is collected by Stealth Falcon malware, it is exfiltrated over the existing C2 channel.[70]

S0491 StrongPity

StrongPity can exfiltrate collected documents through C2 channels.[71][72]

S0467 TajMahal

TajMahal has the ability to send collected files over its C2.[73]

S0595 ThiefQuest

ThiefQuest exfiltrates targeted file extensions in the /Users/ folder to the command and control server via unencrypted HTTP. Network packets contain a string with two pieces of information: a file path and the contents of the file in a base64 encoded string.[74][75]

S0266 TrickBot

TrickBot can send information about the compromised host to a hardcoded C2 server.[76]

S0386 Ursnif

Ursnif has used HTTP POSTs to exfil gathered information.[77][78][79]

S0476 Valak

Valak has the ability to exfiltrate data over the C2 channel.[80][81][82]

G0102 Wizard Spider

Wizard Spider has exfiltrated domain credentials and network enumeration information over command and control (C2) channels.[83]

S0251 Zebrocy

Zebrocy has exfiltrated data to the designated C2 server using HTTP POST requests.[84][85]

G0128 ZIRCONIUM

ZIRCONIUM has exfiltrated files via the Dropbox API C2.[86]

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 activity at the network level. Signatures are often for unique indicators within protocols and may be based on the specific obfuscation technique used by a particular adversary or tool, and will likely be different across various malware families and versions. Adversaries will likely change tool command and control signatures over time or construct protocols in such a way to avoid detection by common defensive tools. [87]

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. [87]

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