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: Binary file metadata, File monitoring, Process command-line parameters, Process monitoring
Version: 1.0
Created: 20 February 2020
Last Modified: 29 March 2020

Procedure Examples

Name Description
ADVSTORESHELL

ADVSTORESHELL encrypts with the 3DES algorithm and a hardcoded key prior to exfiltration.[9]

Agent Tesla

Agent Tesla encrypts the data with 3DES before sending it over the C2 server.[12]

APT28

APT28 used a publicly available tool to gather and compress multiple documents on the DCCC and DNC networks.[28]

APT32

APT32's backdoor has used LZMA compression and RC4 encryption before exfiltration.[31]

Backdoor.Oldrea

Backdoor.Oldrea writes collected data to a temporary file in an encrypted form before exfiltration to a C2 server.[11]

Daserf

Daserf hides collected data in password-protected .rar archives.[3]

Dragonfly 2.0

Dragonfly 2.0 compressed data into .zip files prior to exfiltrating it.[30]

Emotet

Emotet has been observed encrypting the data it collects before sending it to the C2 server. [17]

Empire

Empire can ZIP directories on the target system.[1]

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]

Exaramel for Windows

Exaramel for Windows automatically encrypts files before sending them to the C2 server.[20]

FELIXROOT

FELIXROOT encrypts collected data with AES and Base64 and then sends it to the C2 server.[16]

FIN6

Following data collection, FIN6 has compressed log files into a ZIP archive prior to staging and exfiltration.[24]

Gold Dragon

Gold Dragon encrypts data using Base64 before being sent to the command and control server.[2]

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.[23]

Ke3chang

The Ke3chang group has been known to compress data before exfiltration.[29]

Lazarus Group

Lazarus Group malware RomeoDelta archives specified directories in .zip format, encrypts the .zip file, and uploads it to its C2 server. [25][26][27]

LightNeuron

LightNeuron contains a function to encrypt and store emails that it collects.[19]

Lurid

Lurid can compress data before sending it.[10]

Machete

Machete stores zipped files with profile data from installed web browsers.[21]

menuPass

menuPass has encrypted files and information before exfiltration.[32]

OSX_OCEANLOTUS.D

OSX_OCEANLOTUS.D scrambles and encrypts data using AES256 before sending it to the C2 server.[13]

Patchwork

Patchwork encrypted the collected files' path with AES and then encoded them with base64.[22]

Prikormka

After collecting documents from removable media, Prikormka compresses the collected files, and encrypts it with Blowfish.[4]

Proton

Proton zips up files before exfiltrating them.[8]

Remexi

Remexi encrypts and adds all gathered browser data into files for upload to C2.[18]

RunningRAT

RunningRAT contains code to compress files.[2]

VERMIN

VERMIN encrypts the collected files using 3-DES.[5]

Zebrocy

Zebrocy uses an encryption method similar to RC4 as well as AES to encrypt data before exfiltration. [6][7]

Mitigations

Mitigation Description
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.[33]

References

  1. Schroeder, W., Warner, J., Nelson, M. (n.d.). Github PowerShellEmpire. Retrieved April 28, 2016.
  2. Sherstobitoff, R., Saavedra-Morales, J. (2018, February 02). Gold Dragon Widens Olympics Malware Attacks, Gains Permanent Presence on Victims’ Systems. Retrieved June 6, 2018.
  3. DiMaggio, J. (2016, April 28). Tick cyberespionage group zeros in on Japan. Retrieved July 16, 2018.
  4. Cherepanov, A.. (2016, May 17). Operation Groundbait: Analysis of a surveillance toolkit. Retrieved May 18, 2016.
  5. Lancaster, T., Cortes, J. (2018, January 29). VERMIN: Quasar RAT and Custom Malware Used In Ukraine. Retrieved July 5, 2018.
  6. Kaspersky Lab's Global Research & Analysis Team. (2018, February 20). A Slice of 2017 Sofacy Activity. Retrieved November 27, 2018.
  7. ESET. (2018, November 20). Sednit: What’s going on with Zebrocy?. Retrieved February 12, 2019.
  8. Patrick Wardle. (n.d.). Mac Malware of 2017. Retrieved September 21, 2018.
  9. ESET. (2016, October). En Route with Sednit - Part 2: Observing the Comings and Goings. Retrieved November 21, 2016.
  10. Villeneuve, N., Sancho, D. (2011). THE “LURID” DOWNLOADER. Retrieved November 12, 2014.
  11. Symantec Security Response. (2014, July 7). Dragonfly: Cyberespionage Attacks Against Energy Suppliers. Retrieved April 8, 2016.
  12. Brumaghin, E., et al. (2018, October 15). Old dog, new tricks - Analysing new RTF-based campaign distributing Agent Tesla, Loki with PyREbox. Retrieved November 5, 2018.
  13. Horejsi, J. (2018, April 04). New MacOS Backdoor Linked to OceanLotus Found. Retrieved November 13, 2018.
  14. Kaspersky Lab's Global Research and Analysis Team. (2014, August 7). The Epic Turla Operation: Solving some of the mysteries of Snake/Uroburos. Retrieved December 11, 2014.
  15. Kaspersky Lab's Global Research & Analysis Team. (2014, August 06). The Epic Turla Operation: Solving some of the mysteries of Snake/Uroboros. Retrieved November 7, 2018.
  16. Patil, S. (2018, June 26). Microsoft Office Vulnerabilities Used to Distribute FELIXROOT Backdoor in Recent Campaign. Retrieved July 31, 2018.
  17. Xiaopeng Zhang. (2017, May 3). Deep Analysis of New Emotet Variant – Part 1. Retrieved April 1, 2019.
  1. Legezo, D. (2019, January 30). Chafer used Remexi malware to spy on Iran-based foreign diplomatic entities. Retrieved April 17, 2019.
  2. Faou, M. (2019, May). Turla LightNeuron: One email away from remote code execution. Retrieved June 24, 2019.
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  4. ESET. (2019, July). MACHETE JUST GOT SHARPER Venezuelan government institutions under attack. Retrieved September 13, 2019.
  5. Lunghi, D., et al. (2017, December). Untangling the Patchwork Cyberespionage Group. Retrieved July 10, 2018.
  6. Sherstobitoff, R. (2018, March 02). McAfee Uncovers Operation Honeybee, a Malicious Document Campaign Targeting Humanitarian Aid Groups. Retrieved May 16, 2018.
  7. FireEye Threat Intelligence. (2016, April). Follow the Money: Dissecting the Operations of the Cyber Crime Group FIN6. Retrieved June 1, 2016.
  8. Novetta Threat Research Group. (2016, February 24). Operation Blockbuster: Loaders, Installers and Uninstallers Report. Retrieved March 2, 2016.
  9. Novetta Threat Research Group. (2016, February 24). Operation Blockbuster: Remote Administration Tools & Content Staging Malware Report. Retrieved March 16, 2016.
  10. Sherstobitoff, R. (2018, February 12). Lazarus Resurfaces, Targets Global Banks and Bitcoin Users. Retrieved February 19, 2018.
  11. Mueller, R. (2018, July 13). Indictment - United States of America vs. VIKTOR BORISOVICH NETYKSHO, et al. Retrieved September 13, 2018.
  12. Villeneuve, N., Bennett, J. T., Moran, N., Haq, T., Scott, M., & Geers, K. (2014). OPERATION “KE3CHANG”: Targeted Attacks Against Ministries of Foreign Affairs. Retrieved November 12, 2014.
  13. US-CERT. (2018, March 16). Alert (TA18-074A): Russian Government Cyber Activity Targeting Energy and Other Critical Infrastructure Sectors. Retrieved June 6, 2018.
  14. Dumont, R. (2019, March 20). Fake or Fake: Keeping up with OceanLotus decoys. Retrieved April 1, 2019.
  15. United States District Court Southern District of New York (USDC SDNY) . (2018, December 17). United States of America v. Zhu Hua and Zhang Shilong. Retrieved April 17, 2019.
  16. Wikipedia. (2016, March 31). List of file signatures. Retrieved April 22, 2016.