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T1090.003 Multi-hop Proxy

Adversaries may chain together multiple proxies to disguise the source of malicious traffic. Typically, a defender will be able to identify the last proxy traffic traversed before it enters their network; the defender may or may not be able to identify any previous proxies before the last-hop proxy. This technique makes identifying the original source of the malicious traffic even more difficult by requiring the defender to trace malicious traffic through several proxies to identify its source.

For example, adversaries may construct or use onion routing networks – such as the publicly available Tor network – to transport encrypted C2 traffic through a compromised population, allowing communication with any device within the network.3 Adversaries may also use operational relay box (ORB) networks composed of virtual private servers (VPS), Internet of Things (IoT) devices, smart devices, and end-of-life routers to obfuscate their operations.1

In the case of network infrastructure, it is possible for an adversary to leverage multiple compromised devices to create a multi-hop proxy chain (i.e., Network Devices). By leveraging Patch System Image on routers, adversaries can add custom code to the affected network devices that will implement onion routing between those nodes. This method is dependent upon the Network Boundary Bridging method allowing the adversaries to cross the protected network boundary of the Internet perimeter and into the organization’s Wide-Area Network (WAN). Protocols such as ICMP may be used as a transport.

Similarly, adversaries may abuse peer-to-peer (P2P) and blockchain-oriented infrastructure to implement routing between a decentralized network of peers.2

Item Value
ID T1090.003
Sub-techniques T1090.001, T1090.002, T1090.003, T1090.004
Tactics TA0011
Platforms ESXi, Linux, Network Devices, Windows, macOS
Version 2.4
Created 14 March 2020
Last Modified 24 October 2025

Procedure Examples

ID Name Description
G0007 APT28 APT28 has routed traffic over Tor and VPN servers to obfuscate their activities.26
G0016 APT29 A backdoor used by APT29 created a Tor hidden service to forward traffic from the Tor client to local ports 3389 (RDP), 139 (Netbios), and 445 (SMB) enabling full remote access from outside the network and has also used TOR.3031
S0438 Attor Attor has used Tor for C2 communication.11
S1184 BOLDMOVE BOLDMOVE is capable of relaying traffic from command and control servers to follow-on systems.22
C0004 CostaRicto During CostaRicto, the threat actors used a layer of proxies to manage C2 communications.38
S0687 Cyclops Blink Cyclops Blink has used Tor nodes for C2 traffic.17
S0281 Dok Dok downloads and installs Tor via homebrew.7
S0384 Dridex Dridex can use multiple layers of proxy servers to hide terminal nodes in its infrastructure.21
G1003 Ember Bear Ember Bear has configured multi-hop proxies via ProxyChains within victim environments.25
G0085 FIN4 FIN4 has used Tor to log in to victims’ email accounts.29
C0053 FLORAHOX Activity FLORAHOX Activity has routed traffic through a customized Tor relay network layer.1
S1144 FRP The FRP client can be configured to connect to the server through a proxy.5
G0047 Gamaredon Group Gamaredon Group has used Tor for C2 traffic.37
S0342 GreyEnergy GreyEnergy has used Tor relays for Command and Control servers.8
G0100 Inception Inception used chains of compromised routers to proxy C2 communications between them and cloud service providers.27
S0604 Industroyer Industroyer used Tor nodes for C2.19
S0276 Keydnap Keydnap uses a copy of tor2web proxy for HTTPS communications.6
S0641 Kobalos Kobalos can chain together multiple compromised machines as proxies to reach their final targets.2324
G0065 Leviathan Leviathan has used multi-hop proxies to disguise the source of their malicious traffic.28
G0030 Lotus Blossom Lotus Blossom has used tools such as the publicly available HTran tool for proxying traffic in victim environments.35
S0282 MacSpy MacSpy uses Tor for command and control.7
G1051 Medusa Group Medusa Group has used TOR nodes for communications.323334
S1106 NGLite NGLite has abused NKN infrastructure for its C2 communication.2
S1100 Ninja Ninja has the ability to use a proxy chain with up to 255 hops when using TCP.14
S1107 NKAbuse NKAbuse has abused the NKN public blockchain protocol for its C2 communications.1516
C0014 Operation Wocao During Operation Wocao, threat actors executed commands through the installed web shell via Tor exit nodes.39
C0055 Quad7 Activity Quad7 Activity has routed traffic through chains of compromised network devices for password spray attacks.41
C0056 RedPenguin During RedPenguin, UNC3886 used infrastructure associated with operational relay box (ORB) networks.42
C0059 Salesforce Data Exfiltration During Salesforce Data Exfiltration, threat actors used Tor IPs for voice calls and for the collection of stolen data.40
S0623 Siloscape Siloscape uses Tor to communicate with C2.13
C0052 SPACEHOP Activity SPACEHOP Activity has routed traffic through chains of compromised network devices to proxy C2 communications.1
S0491 StrongPity StrongPity can use multiple layers of proxy servers to hide terminal nodes in its infrastructure.18
S0183 Tor Traffic traversing the Tor network will be forwarded to multiple nodes before exiting the Tor network and continuing on to its intended destination.4
S0022 Uroburos Uroburos can use implants on multiple compromised machines to proxy communications through its worldwide P2P network.12
S0386 Ursnif Ursnif has used Tor for C2.910
G1017 Volt Typhoon Volt Typhoon has used multi-hop proxies for command-and-control infrastructure.36
S0366 WannaCry WannaCry uses Tor for command and control traffic.20
G0128 ZIRCONIUM ZIRCONIUM has utilized an ORB (operational relay box) network – consisting compromised devices such as small office and home office (SOHO) routers, IoT devices, and leased virtual private servers (VPS) – to proxy traffic.1

Mitigations

ID Mitigation Description
M1037 Filter Network Traffic Traffic to known anonymity networks and C2 infrastructure can be blocked through the use of network allow and block lists. It should be noted that this kind of blocking may be circumvented by other techniques like Domain Fronting.

References

  1. Raggi, Michael. (2024, May 22). IOC Extinction? China-Nexus Cyber Espionage Actors Use ORB Networks to Raise Cost on Defenders. Retrieved July 8, 2024. ↩↩↩↩

  2. Robert Falcone, Jeff White, and Peter Renals. (2021, November 7). Targeted Attack Campaign Against ManageEngine ADSelfService Plus Delivers Godzilla Webshells, NGLite Trojan and KdcSponge Stealer. Retrieved February 8, 2024. ↩↩

  3. Wikipedia. (n.d.). Onion Routing. Retrieved October 20, 2020. ↩

  4. Roger Dingledine, Nick Mathewson and Paul Syverson. (2004). Tor: The Second-Generation Onion Router. Retrieved December 21, 2017. ↩

  5. fatedier. (n.d.). What is frp?. Retrieved July 10, 2024. ↩

  6. Patrick Wardle. (2017, January 1). Mac Malware of 2016. Retrieved September 21, 2018. ↩

  7. Patrick Wardle. (n.d.). Mac Malware of 2017. Retrieved September 21, 2018. ↩↩

  8. Cherepanov, A. (2018, October). GREYENERGY A successor to BlackEnergy. Retrieved November 15, 2018. ↩

  9. NJCCIC. (2016, September 27). Ursnif. Retrieved September 12, 2024. ↩

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

  11. Hromcova, Z. (2019, October). AT COMMANDS, TOR-BASED COMMUNICATIONS: MEET ATTOR, A FANTASY CREATURE AND ALSO A SPY PLATFORM. Retrieved May 6, 2020. ↩

  12. FBI et al. (2023, May 9). Hunting Russian Intelligence “Snake” Malware. Retrieved June 8, 2023. ↩

  13. Prizmant, D. (2021, June 7). Siloscape: First Known Malware Targeting Windows Containers to Compromise Cloud Environments. Retrieved June 9, 2021. ↩

  14. Dedola, G. (2022, June 21). APT ToddyCat. Retrieved January 3, 2024. ↩

  15. Bill Toulas. (2023, December 14). New NKAbuse malware abuses NKN blockchain for stealthy comms. Retrieved February 8, 2024. ↩

  16. KASPERSKY GERT. (2023, December 14). Unveiling NKAbuse: a new multiplatform threat abusing the NKN protocol. Retrieved February 8, 2024. ↩

  17. Tudorica, R. et al. (2020, June 30). StrongPity APT - Revealing Trojanized Tools, Working Hours and Infrastructure. Retrieved July 20, 2020. ↩

  18. Dragos Inc.. (2017, June 13). CRASHOVERRIDE Analysis of the Threat to Electric Grid Operations. Retrieved December 18, 2020. ↩

  19. Counter Threat Unit Research Team. (2017, May 18). WCry Ransomware Analysis. Retrieved March 26, 2019. ↩

  20. Check Point Research. (2021, January 4). Stopping Serial Killer: Catching the Next Strike. Retrieved September 7, 2021. ↩

  21. Scott Henderson, Cristiana Kittner, Sarah Hawley & Mark Lechtik, Google Cloud. (2023, January 19). Suspected Chinese Threat Actors Exploiting FortiOS Vulnerability (CVE-2022-42475). Retrieved December 31, 2024. ↩

  22. M.Leveille, M., Sanmillan, I. (2021, February 2). Kobalos – A complex Linux threat to high performance computing infrastructure. Retrieved August 24, 2021. ↩

  23. M.Leveille, M., Sanmillan, I. (2021, January). A WILD KOBALOS APPEARS Tricksy Linux malware goes after HPCs. Retrieved August 24, 2021. ↩

  24. US Cybersecurity & Infrastructure Security Agency et al. (2024, September 5). Russian Military Cyber Actors Target U.S. and Global Critical Infrastructure. Retrieved September 6, 2024. ↩

  25. Hacquebord, F., Remorin, L. (2020, December 17). Pawn Storm’s Lack of Sophistication as a Strategy. Retrieved January 13, 2021. ↩

  26. Symantec. (2018, March 14). Inception Framework: Alive and Well, and Hiding Behind Proxies. Retrieved May 8, 2020. ↩

  27. CISA. (2021, July 19). (AA21-200A) Joint Cybersecurity Advisory – Tactics, Techniques, and Procedures of Indicted APT40 Actors Associated with China’s MSS Hainan State Security Department. Retrieved August 12, 2021. ↩

  28. Vengerik, B. et al.. (2014, December 5). Hacking the Street? FIN4 Likely Playing the Market. Retrieved December 17, 2018. ↩

  29. Dunwoody, M. and Carr, N.. (2016, September 27). No Easy Breach DerbyCon 2016. Retrieved September 12, 2024. ↩

  30. Microsoft Threat Intelligence Center. (2021, October 25). NOBELIUM targeting delegated administrative privileges to facilitate broader attacks. Retrieved March 25, 2022. ↩

  31. Anthony Galiette, Doel Santos. (2024, January 11). Medusa Ransomware Turning Your Files into Stone. Retrieved October 15, 2025. ↩

  32. Check Point. (2025, April 16). The 2025 Ransomware Surge: Context for Medusa’s Rise. Retrieved October 15, 2025. ↩

  33. Threat Hunter Team Symantec and Carbon Black. (2025, March 6). Medusa Ransomware Activity Continues to Increase. Retrieved October 15, 2025. ↩

  34. Joey Chen, Cisco Talos. (2025, February 27). Lotus Blossom espionage group targets multiple industries with different versions of Sagerunex and hacking tools. Retrieved March 15, 2025. ↩

  35. CISA et al.. (2024, February 7). PRC State-Sponsored Actors Compromise and Maintain Persistent Access to U.S. Critical Infrastructure. Retrieved May 15, 2024. ↩

  36. Threat Hunter Team, Symantec and Carbon Black. (2025, April 10). Shuckworm Targets Foreign Military Mission Based in Ukraine. Retrieved July 23, 2025. ↩

  37. The BlackBerry Research and Intelligence Team. (2020, November 12). The CostaRicto Campaign: Cyber-Espionage Outsourced. Retrieved May 24, 2021. ↩

  38. Dantzig, M. v., Schamper, E. (2019, December 19). Operation Wocao: Shining a light on one of China’s hidden hacking groups. Retrieved October 8, 2020. ↩

  39. Google Threat Intelligence Group. (2025, June 4). The Cost of a Call: From Voice Phishing to Data Extortion. Retrieved October 22, 2025. ↩

  40. Microsoft Threat Intelligence. (2024, October 31). Chinese threat actor Storm-0940 uses credentials from password spray attacks from a covert network. Retrieved June 4, 2025. ↩

  41. Lamparski, L. et al. (2025, March 11). Ghost in the Router: China-Nexus Espionage Actor UNC3886 Targets Juniper Routers. Retrieved June 24, 2025. ↩