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T1132 Data Encoding

Adversaries may encode data 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. Use of data encoding may adhere to existing protocol specifications and includes use of ASCII, Unicode, Base64, MIME, or other binary-to-text and character encoding systems.2 3 Some data encoding systems may also result in data compression, such as gzip.

Item Value
ID T1132
Sub-techniques T1132.001, T1132.002
Tactics TA0011
Platforms Linux, Windows, macOS
Version 1.2
Created 31 May 2017
Last Modified 21 April 2023

Procedure Examples

ID Name Description
S0128 BADNEWS After encrypting C2 data, BADNEWS converts it into a hexadecimal representation and then encodes it into base64.6
S0132 H1N1 H1N1 obfuscates C2 traffic with an altered version of base64.8
S0362 Linux Rabbit Linux Rabbit sends the payload from the C2 server as an encoded URL parameter. 7
S0699 Mythic Mythic provides various transform functions to encode and/or randomize C2 data.4
S0386 Ursnif Ursnif has used encoded data in HTTP URLs for C2.5

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 C2 signatures over time or construct protocols in such a way as to avoid detection by common defensive tools. 1

Detection

ID Data Source Data Component
DS0029 Network Traffic Network Traffic Content

References

  1. Gardiner, J., Cova, M., Nagaraja, S. (2014, February). Command & Control Understanding, Denying and Detecting. Retrieved April 20, 2016. ↩

  2. Wikipedia. (2016, December 26). Binary-to-text encoding. Retrieved March 1, 2017. ↩

  3. Wikipedia. (2017, February 19). Character Encoding. Retrieved March 1, 2017. ↩

  4. Thomas, C. (n.d.). Mythc Documentation. Retrieved March 25, 2022. ↩

  5. Proofpoint Staff. (2016, August 25). Nightmare on Tor Street: Ursnif variant Dreambot adds Tor functionality. Retrieved June 5, 2019. ↩

  6. Settle, A., et al. (2016, August 8). MONSOON - Analysis Of An APT Campaign. Retrieved September 22, 2016. ↩

  7. Anomali Labs. (2018, December 6). Pulling Linux Rabbit/Rabbot Malware Out of a Hat. Retrieved March 4, 2019. ↩

  8. Reynolds, J.. (2016, September 14). H1N1: Technical analysis reveals new capabilities – part 2. Retrieved September 26, 2016. ↩