Archive Collected Data: Archive via Custom Method

An adversary may compress or encrypt data that is collected prior to exfiltration using a custom method. Adversaries may choose to use custom archival methods, such as encryption with XOR or stream ciphers implemented with no external library or utility references. Custom implementations of well-known compression algorithms have also been used.[1]

ID: T1560.003
Sub-technique of:  T1560
Tactic: Collection
Platforms: Linux, Windows, macOS
Version: 1.0
Created: 20 February 2020
Last Modified: 25 March 2020
Provided by LAYER 8

Procedure Examples

ID Name Description

ADVSTORESHELL compresses output data generated by command execution with a custom implementation of the Lempel–Ziv–Welch (LZW) algorithm.[1]

S0092 Agent.btz

Agent.btz saves system information into an XML file that is then XOR-encoded.[2]

S0438 Attor

Attor encrypts collected data with a custom implementation of Blowfish and RSA ciphers.[3]


BLUELIGHT has encoded data into a binary blob using XOR.[4]

G0052 CopyKittens

CopyKittens encrypts data with a substitute cipher prior to exfiltration.[5]

S0038 Duqu

Modules can be pushed to and executed by Duqu that copy data to a staging area, compress it, and XOR encrypt it.[6]

G0037 FIN6

FIN6 has encoded data gathered from the victim with a simple substitution cipher and single-byte XOR using the 0xAA key, and Base64 with character permutation.[7][8]


FLASHFLOOD employs the same encoding scheme as SPACESHIP for data it stages. Data is compressed with zlib, and bytes are rotated four times before being XOR'ed with 0x23.[9]

S0503 FrameworkPOS

FrameworkPOS can XOR credit card information before exfiltration.[10]


HAWKBALL has encrypted data with XOR before sending it over the C2 channel.[11]

S0260 InvisiMole

InvisiMole uses a variation of the XOR cipher to encrypt files before exfiltration.[12]

G0094 Kimsuky

Kimsuky has used RC4 encryption before exfil.[13]

G0032 Lazarus Group

A Lazarus Group malware sample encrypts data using a simple byte based XOR operation prior to exfiltration.[14][15][16][17]

S0409 Machete

Machete's collected data is encrypted with AES before exfiltration.[18]


MESSAGETAP has XOR-encrypted and stored contents of SMS messages that matched its target list. [19]

G0129 Mustang Panda

Mustang Panda has encrypted documents with RC4 prior to exfiltration.[20]


NETWIRE has used a custom encryption algorithm to encrypt collected data.[21]

S0439 Okrum

Okrum has used a custom implementation of AES encryption to encrypt collected data.[22]

S0264 OopsIE

OopsIE compresses collected files with a simple character replacement scheme before sending them to its C2 server.[23]


OSX_OCEANLOTUS.D scrambles and encrypts data using AES256 before sending it to the C2 server.[24][25]

S0072 OwaAuth

OwaAuth DES-encrypts captured credentials using the key 12345678 before writing the credentials to a log file.[26]

S0458 Ramsay

Ramsay can store collected documents in a custom container after encrypting and compressing them using RC4 and WinRAR.[27]

S0169 RawPOS

RawPOS encodes credit card data it collected from the victim with XOR.[28][29][30]

S0172 Reaver

Reaver encrypts collected data with an incremental XOR key prior to exfiltration.[31]

S0258 RGDoor

RGDoor encrypts files with XOR before sending them back to the C2 server.[32]

S0448 Rising Sun

Rising Sun can archive data using RC4 encryption and Base64 encoding prior to exfiltration.[33]


Data SPACESHIP copies to the staging area is compressed with zlib. Bytes are rotated by four positions and XOR'ed with 0x23.[9]

S0491 StrongPity

StrongPity can compress and encrypt archived files into multiple .sft files with a repeated xor encryption scheme.[34][35]

S0603 Stuxnet

Stuxnet encrypts exfiltrated data via C2 with static 31-byte long XOR keys.[36]

S0098 T9000

T9000 encrypts collected data using a single byte XOR key.[37]


This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.


ID Data Source Data Component
DS0022 File File Creation
DS0012 Script Script Execution

Custom archival methods can be very difficult to detect, since many of them use standard programming language concepts, such as bitwise operations.


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  18. ESET. (2019, July). MACHETE JUST GOT SHARPER Venezuelan government institutions under attack. Retrieved September 13, 2019.
  19. Leong, R., Perez, D., Dean, T. (2019, October 31). MESSAGETAP: Who’s Reading Your Text Messages?. Retrieved May 11, 2020.
  1. Hamzeloofard, S. (2020, January 31). New wave of PlugX targets Hong Kong | Avira Blog. Retrieved April 13, 2021.
  2. Maniath, S. and Kadam P. (2019, March 19). Dissecting a NETWIRE Phishing Campaign's Usage of Process Hollowing. Retrieved January 7, 2021.
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  4. Lee, B., Falcone, R. (2018, February 23). OopsIE! OilRig Uses ThreeDollars to Deliver New Trojan. Retrieved July 16, 2018.
  5. Horejsi, J. (2018, April 04). New MacOS Backdoor Linked to OceanLotus Found. Retrieved November 13, 2018.
  6. Magisa, L. (2020, November 27). New MacOS Backdoor Connected to OceanLotus Surfaces. Retrieved December 2, 2020.
  7. Dell SecureWorks Counter Threat Unit Threat Intelligence. (2015, August 5). Threat Group-3390 Targets Organizations for Cyberespionage. Retrieved August 18, 2018.
  8. Sanmillan, I.. (2020, May 13). Ramsay: A cyber‑espionage toolkit tailored for air‑gapped networks. Retrieved May 27, 2020.
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  10. Bromiley, M. and Lewis, P. (2016, October 7). Attacking the Hospitality and Gaming Industries: Tracking an Attacker Around the World in 7 Years. Retrieved October 6, 2017.
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  12. Grunzweig, J. and Miller-Osborn, J. (2017, November 10). New Malware with Ties to SunOrcal Discovered. Retrieved November 16, 2017.
  13. Falcone, R. (2018, January 25). OilRig uses RGDoor IIS Backdoor on Targets in the Middle East. Retrieved July 6, 2018.
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  17. Nicolas Falliere, Liam O. Murchu, Eric Chien. (2011, February). W32.Stuxnet Dossier. Retrieved December 7, 2020.
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