Data Encoding: Standard Encoding

ID Name
T1132.001 Standard Encoding
T1132.002 Non-Standard Encoding

Adversaries may encode data with a standard data encoding system to make the content of command and control traffic more difficult to detect. Command and control (C2) information can be encoded using a standard data encoding system that adheres to existing protocol specifications. Common data encoding schemes include ASCII, Unicode, hexadecimal, Base64, and MIME.[1] [2] Some data encoding systems may also result in data compression, such as gzip.

ID: T1132.001
Sub-technique of:  T1132
Platforms: Linux, Windows, macOS
Permissions Required: User
Version: 1.0
Created: 14 March 2020
Last Modified: 14 March 2020
Provided by LAYER 8

Procedure Examples

ID Name Description

C2 traffic from ADVSTORESHELL is encrypted, then encoded with Base64 encoding.[3]

G0073 APT19

An APT19 HTTP malware variant used Base64 to encode communications to the C2 server.[4]

G0064 APT33

APT33 has used base64 to encode command and control traffic.[5]

S0373 Astaroth

Astaroth encodes data using Base64 before sending it to the C2 server. [6]

S0129 AutoIt backdoor

AutoIt backdoor has sent a C2 response that was base64-encoded.[7]

S0414 BabyShark

BabyShark has encoded data using certutil before exfiltration.[8]

S0093 Backdoor.Oldrea

Some Backdoor.Oldrea samples use standard Base64 + bzip2, and some use standard Base64 + reverse XOR + RSA-2048 to decrypt data received from C2 servers.[9]


BADNEWS encodes C2 traffic with base64.[7][10][11]

S0268 Bisonal

Bisonal has encoded binary data with Base64.[12]


BLINDINGCAN has encoded its C2 traffic with Base64.[13]


Several BRONZE BUTLER tools encode data with base64 when posting it to a C2 server.[14]

S0014 BS2005

BS2005 uses Base64 encoding for communication in the message body of an HTTP request.[15]

S0030 Carbanak

Carbanak encodes the message body of HTTP traffic with Base64.[16][17]

S0631 Chaes

Chaes has used Base64 to encode C2 communications.[18]

S0144 ChChes

ChChes can encode C2 data with a custom technique that utilizes Base64.[19][20]

S0154 Cobalt Strike

Cobalt Strike can use Base64, URL-safe Base64, or NetBIOS encoding in its C2 traffic.[21]

S0338 Cobian RAT

Cobian RAT obfuscates communications with the C2 server using Base64 encoding.[22]


CORESHELL C2 messages are Base64-encoded.[23]

S0187 Daserf

Daserf uses custom base64 encoding to obfuscate HTTP traffic.[14]

S0354 Denis

Denis encodes the data sent to the server in Base64.[24]

S0200 Dipsind

Dipsind encodes C2 traffic with base64.[25]

S0472 down_new

down_new has the ability to base64 encode C2 communications.[26]

S0377 Ebury

Ebury has encoded C2 traffic in hexadecimal format.[27]

S0081 Elise

Elise exfiltrates data using cookie values that are Base64-encoded.[28]

S0171 Felismus

Some Felismus samples use a custom method for C2 traffic that utilizes Base64.[29]

S0410 Fysbis

Fysbis can use Base64 to encode its C2 traffic.[30]

S0032 gh0st RAT

gh0st RAT has used Zlib to compress C2 communications data before encrypting it.[31]

S0632 GrimAgent

GrimAgent can base64 encode C2 replies.[32]


HAFNIUM has used ASCII encoding for C2 traffic.[33]

S0170 Helminth

For C2 over HTTP, Helminth encodes data with base64 and sends it via the "Cookie" field of HTTP requests. For C2 over DNS, Helminth converts ASCII characters into their hexadecimal values and sends the data in cleartext.[34]


HOPLIGHT has utilized Zlib compression to obfuscate the communications payload. [35]

S0015 Ixeshe

Ixeshe uses custom Base64 encoding schemes to obfuscate command and control traffic in the message body of HTTP requests.[36][37]


A JHUHUGIT variant encodes C2 POST data base64.[38]

S0265 Kazuar

Kazuar encodes communications to the C2 server in Base64.[39]

S0487 Kessel

Kessel has exfiltrated data via hexadecimal-encoded subdomain fields of DNS queries.[40]


KONNI has used a custom base64 key to encode stolen data before exfiltration.[41]

G0032 Lazarus Group

A Lazarus Group malware sample encodes data with base64.[42]

S0409 Machete

Machete has used base64 encoding.[43]

S0459 MechaFlounder

MechaFlounder has the ability to use base16 encoded strings in C2.[44]

S0084 Mis-Type

Mis-Type uses Base64 encoding for C2 traffic.[45]

S0083 Misdat

Misdat network traffic is Base64-encoded plaintext.[45]

S0284 More_eggs

More_eggs has used basE91 encoding, along with encryption, for C2 communication.[46]

G0069 MuddyWater

MuddyWater has used tools to encode C2 communications including Base64 encoding.[47][48]

S0385 njRAT

njRAT uses Base64 encoding for C2 traffic.[49]

S0340 Octopus

Octopus encodes C2 communications in Base64.[50]

S0439 Okrum

Okrum has used base64 to encode C2 communication.[51]

S0264 OopsIE

OopsIE encodes data in hexadecimal format over the C2 channel.[52]

G0040 Patchwork

Patchwork used Base64 to encode C2 traffic.[53]

S0124 Pisloader

Responses from the Pisloader C2 server are base32-encoded.[54]

S0441 PowerShower

PowerShower has the ability to encode C2 communications with base64 encoding.[55][56]


POWERSTATS encoded C2 traffic with base64.[57]


POWRUNER can use base64 encoded C2 communications.[58]

S0113 Prikormka

Prikormka encodes C2 traffic with Base64.[59]

S0650 QakBot

QakBot can Base64 encode system information sent to C2.[60][61]


QUADAGENT encodes C2 communications with base64.[62]

S0458 Ramsay

Ramsay has used base64 to encode its C2 traffic.[63]

S0495 RDAT

RDAT can communicate with the C2 via base32-encoded subdomains.[64]

S0379 Revenge RAT

Revenge RAT uses Base64 to encode information sent to the C2 server.[65]

S0270 RogueRobin

RogueRobin base64 encodes strings that are sent to the C2 over its DNS tunnel.[66]

S0085 S-Type

S-Type uses Base64 encoding for C2 traffic.[45]

G0034 Sandworm Team

Sandworm Team's BCS-server tool uses base64 encoding and HTML tags for the communication traffic between the C2 server.[67]

S0053 SeaDuke

SeaDuke C2 traffic is base64-encoded.[68]

S0610 SideTwist

SideTwist has used Base64 for encoded C2 traffic.[69]

S0633 Sliver

Sliver can use standard encoding techniques like gzip and hex to ASCII to encode the C2 communication payload.[70]


SMOKEDHAM has encoded its C2 traffic with Base64.[71]

S0543 Spark

Spark has encoded communications with the C2 server with base64.[72]

S0374 SpeakUp

SpeakUp encodes C&C communication using Base64. [73]

S0603 Stuxnet

Stuxnet transforms encrypted binary data into an ASCII string in order to use it as a URL parameter value.[74]


SUNBURST used Base64 encoding in its C2 traffic.[75]

G0127 TA551

TA551 has used encoded ASCII text for initial C2 communications.[76]

S0266 TrickBot

TrickBot can Base64-encode C2 commands.[77]

G0081 Tropic Trooper

Tropic Trooper has used base64 encoding to hide command strings delivered from the C2.[78]

S0476 Valak

Valak has returned C2 data as encoded ASCII.[76]

S0514 WellMess

WellMess has used Base64 encoding to uniquely identify communication to and from the C2.[79]

S0653 xCaon

xCaon has used Base64 to encode its C2 traffic.[80]

S0251 Zebrocy

Zebrocy has used URL/Percent Encoding on data exfiltrated via HTTP POST requests.[81]


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 C2 signatures over time or construct protocols in such a way as to avoid detection by common defensive tools.


ID Data Source Data Component
DS0029 Network Traffic Network Traffic Content

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.[82]


  1. Wikipedia. (2016, December 26). Binary-to-text encoding. Retrieved March 1, 2017.
  2. Wikipedia. (2017, February 19). Character Encoding. Retrieved March 1, 2017.
  3. Kaspersky Lab's Global Research and Analysis Team. (2015, December 4). Sofacy APT hits high profile targets with updated toolset. Retrieved December 10, 2015.
  4. Grunzweig, J., Lee, B. (2016, January 22). New Attacks Linked to C0d0so0 Group. Retrieved August 2, 2018.
  5. Ackerman, G., et al. (2018, December 21). OVERRULED: Containing a Potentially Destructive Adversary. Retrieved January 17, 2019.
  6. Doaty, J., Garrett, P.. (2018, September 10). We’re Seeing a Resurgence of the Demonic Astaroth WMIC Trojan. Retrieved April 17, 2019.
  7. Settle, A., et al. (2016, August 8). MONSOON - Analysis Of An APT Campaign. Retrieved September 22, 2016.
  8. Unit 42. (2019, February 22). New BabyShark Malware Targets U.S. National Security Think Tanks. Retrieved October 7, 2019.
  9. Symantec Security Response. (2014, July 7). Dragonfly: Cyberespionage Attacks Against Energy Suppliers. Retrieved April 8, 2016.
  10. Levene, B. et al.. (2018, March 7). Patchwork Continues to Deliver BADNEWS to the Indian Subcontinent. Retrieved March 31, 2018.
  11. Lunghi, D., et al. (2017, December). Untangling the Patchwork Cyberespionage Group. Retrieved July 10, 2018.
  12. Zykov, K. (2020, August 13). CactusPete APT group’s updated Bisonal backdoor. Retrieved May 5, 2021.
  13. US-CERT. (2020, August 19). MAR-10295134-1.v1 – North Korean Remote Access Trojan: BLINDINGCAN. Retrieved August 19, 2020.
  14. Counter Threat Unit Research Team. (2017, October 12). BRONZE BUTLER Targets Japanese Enterprises. Retrieved January 4, 2018.
  15. 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.
  16. Kaspersky Lab's Global Research and Analysis Team. (2015, February). CARBANAK APT THE GREAT BANK ROBBERY. Retrieved August 23, 2018.
  17. Bennett, J., Vengerik, B. (2017, June 12). Behind the CARBANAK Backdoor. Retrieved June 11, 2018.
  18. Salem, E. (2020, November 17). CHAES: Novel Malware Targeting Latin American E-Commerce. Retrieved June 30, 2021.
  19. Miller-Osborn, J. and Grunzweig, J.. (2017, February 16). menuPass Returns with New Malware and New Attacks Against Japanese Academics and Organizations. Retrieved March 1, 2017.
  20. Nakamura, Y.. (2017, February 17). ChChes - Malware that Communicates with C&C Servers Using Cookie Headers. Retrieved March 1, 2017.
  21. Strategic Cyber LLC. (2020, November 5). Cobalt Strike: Advanced Threat Tactics for Penetration Testers. Retrieved April 13, 2021.
  22. Yadav, A., et al. (2017, August 31). Cobian RAT – A backdoored RAT. Retrieved November 13, 2018.
  23. FireEye. (2015). APT28: A WINDOW INTO RUSSIA’S CYBER ESPIONAGE OPERATIONS?. Retrieved August 19, 2015.
  24. Dahan, A. (2017). Operation Cobalt Kitty. Retrieved December 27, 2018.
  25. Windows Defender Advanced Threat Hunting Team. (2016, April 29). PLATINUM: Targeted attacks in South and Southeast Asia. Retrieved February 15, 2018.
  26. Chen, J. et al. (2019, November). Operation ENDTRADE: TICK’s Multi-Stage Backdoors for Attacking Industries and Stealing Classified Data. Retrieved June 9, 2020.
  27. M.Léveillé, M.. (2014, February 21). An In-depth Analysis of Linux/Ebury. Retrieved April 19, 2019.
  28. Falcone, R., et al.. (2015, June 16). Operation Lotus Blossom. Retrieved February 15, 2016.
  29. Somerville, L. and Toro, A. (2017, March 30). Playing Cat & Mouse: Introducing the Felismus Malware. Retrieved November 16, 2017.
  30. Doctor Web. (2014, November 21). Linux.BackDoor.Fysbis.1. Retrieved December 7, 2017.
  31. Quinn, J. (2019, March 25). The odd case of a Gh0stRAT variant. Retrieved July 15, 2020.
  32. Priego, A. (2021, July). THE BROTHERS GRIM: THE REVERSING TALE OF GRIMAGENT MALWARE USED BY RYUK. Retrieved July 16, 2021.
  33. MSTIC. (2021, March 2). HAFNIUM targeting Exchange Servers with 0-day exploits. Retrieved March 3, 2021.
  34. Falcone, R. and Lee, B.. (2016, May 26). The OilRig Campaign: Attacks on Saudi Arabian Organizations Deliver Helminth Backdoor. Retrieved May 3, 2017.
  35. US-CERT. (2019, April 10). MAR-10135536-8 – North Korean Trojan: HOPLIGHT. Retrieved April 19, 2019.
  36. Moran, N., & Villeneuve, N. (2013, August 12). Survival of the Fittest: New York Times Attackers Evolve Quickly [Blog]. Retrieved November 12, 2014.
  37. Sancho, D., et al. (2012, May 22). IXESHE An APT Campaign. Retrieved June 7, 2019.
  38. Unit 42. (2017, December 15). Unit 42 Playbook Viewer. Retrieved December 20, 2017.
  39. Levene, B, et al. (2017, May 03). Kazuar: Multiplatform Espionage Backdoor with API Access. Retrieved July 17, 2018.
  40. Dumont, R., M.Léveillé, M., Porcher, H. (2018, December 1). THE DARK SIDE OF THE FORSSHE A landscape of OpenSSH backdoors. Retrieved July 16, 2020.
  41. Karmi, D. (2020, January 4). A Look Into Konni 2019 Campaign. Retrieved April 28, 2020.
  1. Sherstobitoff, R. (2018, February 12). Lazarus Resurfaces, Targets Global Banks and Bitcoin Users. Retrieved February 19, 2018.
  2. Kaspersky Global Research and Analysis Team. (2014, August 20). El Machete. Retrieved September 13, 2019.
  3. Falcone, R. (2019, March 4). New Python-Based Payload MechaFlounder Used by Chafer. Retrieved May 27, 2020.
  4. Gross, J. (2016, February 23). Operation Dust Storm. Retrieved September 19, 2017.
  5. Villadsen, O.. (2019, August 29). More_eggs, Anyone? Threat Actor ITG08 Strikes Again. Retrieved September 16, 2019.
  6. ClearSky. (2019, June). Iranian APT group ‘MuddyWater’ Adds Exploits to Their Arsenal. Retrieved May 14, 2020.
  7. Peretz, A. and Theck, E. (2021, March 5). Earth Vetala – MuddyWater Continues to Target Organizations in the Middle East. Retrieved March 18, 2021.
  8. Fidelis Cybersecurity. (2013, June 28). Fidelis Threat Advisory #1009: "njRAT" Uncovered. Retrieved June 4, 2019.
  9. Kaspersky Lab's Global Research & Analysis Team. (2018, October 15). Octopus-infested seas of Central Asia. Retrieved November 14, 2018.
  10. Hromcova, Z. (2019, July). OKRUM AND KETRICAN: AN OVERVIEW OF RECENT KE3CHANG GROUP ACTIVITY. Retrieved May 6, 2020.
  11. Lee, B., Falcone, R. (2018, February 23). OopsIE! OilRig Uses ThreeDollars to Deliver New Trojan. Retrieved July 16, 2018.
  12. Cymmetria. (2016). Unveiling Patchwork - The Copy-Paste APT. Retrieved August 3, 2016.
  13. Grunzweig, J., et al. (2016, May 24). New Wekby Attacks Use DNS Requests As Command and Control Mechanism. Retrieved August 17, 2016.
  14. Lancaster, T. (2018, November 5). Inception Attackers Target Europe with Year-old Office Vulnerability. Retrieved May 8, 2020.
  15. GReAT. (2019, August 12). Recent Cloud Atlas activity. Retrieved May 8, 2020.
  16. Lancaster, T.. (2017, November 14). Muddying the Water: Targeted Attacks in the Middle East. Retrieved March 15, 2018.
  17. Sardiwal, M, et al. (2017, December 7). New Targeted Attack in the Middle East by APT34, a Suspected Iranian Threat Group, Using CVE-2017-11882 Exploit. Retrieved December 20, 2017.
  18. Cherepanov, A.. (2016, May 17). Operation Groundbait: Analysis of a surveillance toolkit. Retrieved May 18, 2016.
  19. CS. (2020, October 7). Duck Hunting with Falcon Complete: A Fowl Banking Trojan Evolves, Part 2. Retrieved September 27, 2021.
  20. Kuzmenko, A. et al. (2021, September 2). QakBot technical analysis. Retrieved September 27, 2021.
  21. Lee, B., Falcone, R. (2018, July 25). OilRig Targets Technology Service Provider and Government Agency with QUADAGENT. Retrieved August 9, 2018.
  22. Antiy CERT. (2020, April 20). Analysis of Ramsay components of Darkhotel's infiltration and isolation network. Retrieved March 24, 2021.
  23. Falcone, R. (2020, July 22). OilRig Targets Middle Eastern Telecommunications Organization and Adds Novel C2 Channel with Steganography to Its Inventory. Retrieved July 28, 2020.
  24. Livelli, K, et al. (2018, November 12). Operation Shaheen. Retrieved May 1, 2019.
  25. Falcone, R., et al. (2018, July 27). New Threat Actor Group DarkHydrus Targets Middle East Government. Retrieved August 2, 2018.
  26. Cherepanov, A.. (2016, December 13). The rise of TeleBots: Analyzing disruptive KillDisk attacks. Retrieved June 10, 2020.
  27. Grunzweig, J.. (2015, July 14). Unit 42 Technical Analysis: Seaduke. Retrieved August 3, 2016.
  28. Check Point. (2021, April 8). Iran’s APT34 Returns with an Updated Arsenal. Retrieved May 5, 2021.
  29. BishopFox. (n.d.). Sliver HTTP(S) C2. Retrieved September 16, 2021.
  30. FireEye. (2021, June 16). Smoking Out a DARKSIDE Affiliate’s Supply Chain Software Compromise. Retrieved September 22, 2021.
  31. Falcone, R., et al. (2020, March 3). Molerats Delivers Spark Backdoor to Government and Telecommunications Organizations. Retrieved December 14, 2020.
  32. Check Point Research. (2019, February 4). SpeakUp: A New Undetected Backdoor Linux Trojan. Retrieved April 17, 2019.
  33. Nicolas Falliere, Liam O. Murchu, Eric Chien. (2011, February). W32.Stuxnet Dossier. Retrieved December 7, 2020.
  34. FireEye. (2020, December 13). Highly Evasive Attacker Leverages SolarWinds Supply Chain to Compromise Multiple Global Victims With SUNBURST Backdoor. Retrieved January 4, 2021.
  35. Duncan, B. (2020, July 24). Evolution of Valak, from Its Beginnings to Mass Distribution. Retrieved August 31, 2020.
  36. Dahan, A. et al. (2019, December 11). DROPPING ANCHOR: FROM A TRICKBOT INFECTION TO THE DISCOVERY OF THE ANCHOR MALWARE. Retrieved September 10, 2020.
  37. Chen, J.. (2020, May 12). Tropic Trooper’s Back: USBferry Attack Targets Air gapped Environments. Retrieved May 20, 2020.
  38. CISA. (2020, July 16). MAR-10296782-2.v1 – WELLMESS. Retrieved September 24, 2020.
  39. CheckPoint Research. (2021, July 1). IndigoZebra APT continues to attack Central Asia with evolving tools. Retrieved September 24, 2021.
  40. Accenture Security. (2018, November 29). SNAKEMACKEREL. Retrieved April 15, 2019.
  41. Gardiner, J., Cova, M., Nagaraja, S. (2014, February). Command & Control Understanding, Denying and Detecting. Retrieved April 20, 2016.