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T1102.003 One-Way Communication

Adversaries may use an existing, legitimate external Web service as a means for sending commands to a compromised system without receiving return output over the Web service channel. Compromised systems may leverage popular websites and social media to host command and control (C2) instructions. Those infected systems may opt to send the output from those commands back over a different C2 channel, including to another distinct Web service. Alternatively, compromised systems may return no output at all in cases where adversaries want to send instructions to systems and do not want a response.

Popular websites and social media acting as a mechanism for C2 may give a significant amount of cover due to the likelihood that hosts within a network are already communicating with them prior to a compromise. Using common services, such as those offered by Google or Twitter, makes it easier for adversaries to hide in expected noise. Web service providers commonly use SSL/TLS encryption, giving adversaries an added level of protection.

Item Value
ID T1102.003
Sub-techniques T1102.001, T1102.002, T1102.003
Tactics TA0011
Platforms Linux, Windows, macOS
Permissions required User
Version 1.0
Created 14 March 2020
Last Modified 26 March 2020

Procedure Examples

ID Name Description
S0568 EVILNUM EVILNUM has used a one-way communication method via GitLab and Digital Point to perform C2.3
S0037 HAMMERTOSS The “tDiscoverer” variant of HAMMERTOSS establishes a C2 channel by downloading resources from Web services like Twitter and GitHub. HAMMERTOSS binaries contain an algorithm that generates a different Twitter handle for the malware to check for instructions every day.2
G0065 Leviathan Leviathan has received C2 instructions from user profiles created on legitimate websites such as Github and TechNet.8
S0455 Metamorfo Metamorfo has downloaded a zip file for execution on the system.567
S0052 OnionDuke OnionDuke uses Twitter as a backup C2.4

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.
M1021 Restrict Web-Based Content Web proxies can be used to enforce external network communication policy that prevents use of unauthorized external services.

Detection

ID Data Source Data Component
DS0029 Network Traffic Network Connection Creation

References

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

  2. FireEye Labs. (2015, July). HAMMERTOSS: Stealthy Tactics Define a Russian Cyber Threat Group. Retrieved September 17, 2015. ↩

  3. Adamitis, D. (2020, May 6). Phantom in the Command Shell. Retrieved December 22, 2021. ↩

  4. F-Secure Labs. (2015, September 17). The Dukes: 7 years of Russian cyberespionage. Retrieved December 10, 2015. ↩

  5. Erlich, C. (2020, April 3). The Avast Abuser: Metamorfo Banking Malware Hides By Abusing Avast Executable. Retrieved May 26, 2020. ↩

  6. Sierra, E., Iglesias, G.. (2018, April 24). Metamorfo Campaigns Targeting Brazilian Users. Retrieved July 30, 2020. ↩

  7. Zhang, X. (2020, February 4). Another Metamorfo Variant Targeting Customers of Financial Institutions in More Countries. Retrieved July 30, 2020. ↩

  8. FireEye. (2018, March 16). Suspected Chinese Cyber Espionage Group (TEMP.Periscope) Targeting U.S. Engineering and Maritime Industries. Retrieved April 11, 2018. ↩