Archive Collected Data

An adversary may compress and/or encrypt data that is collected prior to exfiltration. Compressing the data can help to obfuscate the collected data and minimize the amount of data sent over the network. Encryption can be used to hide information that is being exfiltrated from detection or make exfiltration less conspicuous upon inspection by a defender.

Both compression and encryption are done prior to exfiltration, and can be performed using a utility, 3rd party library, or custom method.

ID: T1560
Sub-techniques:  T1560.001, T1560.002, T1560.003
Tactic: Collection
Platforms: Linux, Windows, macOS
Data Sources: Command: Command Execution, File: File Creation, Process: Process Creation, Script: Script Execution
Version: 1.0
Created: 20 February 2020
Last Modified: 21 October 2020

Procedure Examples

ID Name Description
S0045 ADVSTORESHELL

ADVSTORESHELL encrypts with the 3DES algorithm and a hardcoded key prior to exfiltration.[1]

S0331 Agent Tesla

Agent Tesla can encrypt data with 3DES before sending it over to a C2 server.[2]

G0007 APT28

APT28 used a publicly available tool to gather and compress multiple documents on the DCCC and DNC networks.[3]

G0050 APT32

APT32's backdoor has used LZMA compression and RC4 encryption before exfiltration.[4]

S0456 Aria-body

Aria-body has used ZIP to compress data gathered on a compromised host.[5]

S0093 Backdoor.Oldrea

Backdoor.Oldrea writes collected data to a temporary file in an encrypted form before exfiltration to a C2 server.[6]

S0521 BloodHound

BloodHound can compress data collected by its SharpHound ingestor into a ZIP file to be written to disk.[7]

S0454 Cadelspy

Cadelspy has the ability to compress stolen data into a .cab file.[8]

S0187 Daserf

Daserf hides collected data in password-protected .rar archives.[9]

G0074 Dragonfly 2.0

Dragonfly 2.0 compressed data into .zip files prior to exfiltrating it.[10]

S0567 Dtrack

Dtrack packs collected data into a password protected archive.[11]

S0367 Emotet

Emotet has been observed encrypting the data it collects before sending it to the C2 server. [12]

S0363 Empire

Empire can ZIP directories on the target system.[13]

S0091 Epic

Epic encrypts collected data using a public key framework before sending it over the C2 channel.[14] Some variants encrypt the collected data with AES and encode it with base64 before transmitting it to the C2 server.[15]

S0343 Exaramel for Windows

Exaramel for Windows automatically encrypts files before sending them to the C2 server.[16]

S0267 FELIXROOT

FELIXROOT encrypts collected data with AES and Base64 and then sends it to the C2 server.[17]

G0037 FIN6

Following data collection, FIN6 has compressed log files into a ZIP archive prior to staging and exfiltration.[18]

S0249 Gold Dragon

Gold Dragon encrypts data using Base64 before being sent to the command and control server.[19]

G0072 Honeybee

Honeybee adds collected files to a temp.zip file saved in the %temp% folder, then base64 encodes it and uploads it to control server.[20]

G0004 Ke3chang

The Ke3chang group has been known to compress data before exfiltration.[21]

S0487 Kessel

Kessel can RC4-encrypt credentials before sending to the C2.[22]

G0032 Lazarus Group

Lazarus Group malware RomeoDelta archives specified directories in .zip format, encrypts the .zip file, and uploads it to its C2 server. [23][24][25]

S0395 LightNeuron

LightNeuron contains a function to encrypt and store emails that it collects.[26]

S0010 Lurid

Lurid can compress data before sending it.[27]

S0409 Machete

Machete stores zipped files with profile data from installed web browsers.[28]

G0045 menuPass

menuPass has encrypted files and information before exfiltration.[29][30]

S0198 NETWIRE

NETWIRE has the ability to compress archived screenshots.[31]

S0352 OSX_OCEANLOTUS.D

OSX_OCEANLOTUS.D scrambles and encrypts data using AES256 before sending it to the C2 server.[32][33]

G0040 Patchwork

Patchwork encrypted the collected files' path with AES and then encoded them with base64.[34]

S0517 Pillowmint

Pillowmint has encrypted stolen credit card information with AES and further encoded it with Base64.[35]

S0113 Prikormka

After collecting documents from removable media, Prikormka compresses the collected files, and encrypts it with Blowfish.[36]

S0279 Proton

Proton zips up files before exfiltrating them.[37]

S0375 Remexi

Remexi encrypts and adds all gathered browser data into files for upload to C2.[38]

S0253 RunningRAT

RunningRAT contains code to compress files.[19]

S0445 ShimRatReporter

ShimRatReporter used LZ compression to compress initial reconnaissance reports before sending to the C2.[39]

S0586 TAINTEDSCRIBE

TAINTEDSCRIBE has used FileReadZipSend to compress a file and send to C2.[40]

S0257 VERMIN

VERMIN encrypts the collected files using 3-DES.[41]

S0515 WellMail

WellMail can archive files on the compromised host.[42]

S0251 Zebrocy

Zebrocy has used a method similar to RC4 as well as AES for encryption and hexadecimal for encoding data before exfiltration. [43][44][45]

Mitigations

ID Mitigation Description
M1047 Audit

System scans can be performed to identify unauthorized archival utilities.

Detection

Archival software and archived files can be detected in many ways. Common utilities that may be present on the system or brought in by an adversary may be detectable through process monitoring and monitoring for command-line arguments for known archival utilities. This may yield a significant number of benign events, depending on how systems in the environment are typically used.

A process that loads the Windows DLL crypt32.dll may be used to perform encryption, decryption, or verification of file signatures.

Consider detecting writing of files with extensions and/or headers associated with compressed or encrypted file types. Detection efforts may focus on follow-on exfiltration activity, where compressed or encrypted files can be detected in transit with a network intrusion detection or data loss prevention system analyzing file headers.[46]

References

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