T1090.003: Multi-hop Proxy — MITRE ATT&CK Technique

Description

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.(Citation: Onion Routing) 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.(Citation: ORB Mandiant)

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.(Citation: NGLite Trojan)

Platforms

ESXiLinuxmacOSNetwork DevicesWindows

Mitigations (1)

Filter Network TrafficM1037

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.

Threat Groups (11)

ID	Group	Context
G1003	Ember Bear	[Ember Bear](https://attack.mitre.org/groups/G1003) has configured multi-hop proxies via ProxyChains within victim environments.(Citation: CISA GRU291...
G0007	APT28	[APT28](https://attack.mitre.org/groups/G0007) has routed traffic over [Tor](https://attack.mitre.org/software/S0183) and VPN servers to obfuscate the...
G0100	Inception	[Inception](https://attack.mitre.org/groups/G0100) used chains of compromised routers to proxy C2 communications between them and cloud service provid...
G0065	Leviathan	[Leviathan](https://attack.mitre.org/groups/G0065) has used multi-hop proxies to disguise the source of their malicious traffic.(Citation: CISA AA21-2...
G0085	FIN4	[FIN4](https://attack.mitre.org/groups/G0085) has used [Tor](https://attack.mitre.org/software/S0183) to log in to victims' email accounts.(Citation: ...
G0016	APT29	A backdoor used by [APT29](https://attack.mitre.org/groups/G0016) created a [Tor](https://attack.mitre.org/software/S0183) hidden service to forward t...
G1051	Medusa Group	[Medusa Group](https://attack.mitre.org/groups/G1051) has used TOR nodes for communications.(Citation: Palo Alto Unit 42 Medusa Group Medusa Ransomwar...
G0030	Lotus Blossom	[Lotus Blossom](https://attack.mitre.org/groups/G0030) has used tools such as the publicly available HTran tool for proxying traffic in victim environ...
G0128	ZIRCONIUM	[ZIRCONIUM](https://attack.mitre.org/groups/G0128) has utilized an ORB (operational relay box) network – consisting compromised devices such as small ...
G1017	Volt Typhoon	[Volt Typhoon](https://attack.mitre.org/groups/G1017) has used multi-hop proxies for command-and-control infrastructure.(Citation: CISA AA24-038A PRC ...
G0047	Gamaredon Group	[Gamaredon Group](https://attack.mitre.org/groups/G0047) has used [Tor](https://attack.mitre.org/software/S0183) for C2 traffic.(Citation: SymantecCar...

Associated Software (22)

ID	Name	Type	Context
S0276	Keydnap	Malware	[Keydnap](https://attack.mitre.org/software/S0276) uses a copy of tor2web proxy for HTTPS communications.(Citation: synack 2016 review)
S0282	MacSpy	Malware	[MacSpy](https://attack.mitre.org/software/S0282) uses [Tor](https://attack.mitre.org/software/S0183) for command and control.(Citation: objsee mac ma...
S0342	GreyEnergy	Malware	[GreyEnergy](https://attack.mitre.org/software/S0342) has used [Tor](https://attack.mitre.org/software/S0183) relays for Command and Control servers.(...
S0386	Ursnif	Malware	[Ursnif](https://attack.mitre.org/software/S0386) has used [Tor](https://attack.mitre.org/software/S0183) for C2.(Citation: NJCCIC Ursnif Sept 2016)(C...
S0438	Attor	Malware	[Attor](https://attack.mitre.org/software/S0438) has used [Tor](https://attack.mitre.org/software/S0183) for C2 communication.(Citation: ESET Attor Oc...
S1087	AsyncRAT	Tool	[AsyncRAT](https://attack.mitre.org/software/S1087) can proxy C2 through a [Tor](https://attack.mitre.org/software/S0183) client.(Citation: ESET Mirro...
S0022	Uroburos	Malware	[Uroburos](https://attack.mitre.org/software/S0022) can use implants on multiple compromised machines to proxy communications through its worldwide P2...
S0623	Siloscape	Malware	[Siloscape](https://attack.mitre.org/software/S0623) uses [Tor](https://attack.mitre.org/software/S0183) to communicate with C2.(Citation: Unit 42 Sil...
S9001	SystemBC	Malware	[SystemBC](https://attack.mitre.org/software/S9001) has used multiple proxy layers, such as SOCKS5 and [Tor](https://attack.mitre.org/software/S0183),...
S1100	Ninja	Malware	[Ninja](https://attack.mitre.org/software/S1100) has the ability to use a proxy chain with up to 255 hops when using TCP.(Citation: Kaspersky ToddyCat...
S0183	Tor	Tool	Traffic traversing the [Tor](https://attack.mitre.org/software/S0183) network will be forwarded to multiple nodes before exiting the [Tor](https://att...
S1107	NKAbuse	Malware	[NKAbuse](https://attack.mitre.org/software/S1107) has abused the NKN public blockchain protocol for its C2 communications.(Citation: NKAbuse BC)(Cita...
S1144	FRP	Tool	The [FRP](https://attack.mitre.org/software/S1144) client can be configured to connect to the server through a proxy.(Citation: FRP GitHub)
S0281	Dok	Malware	[Dok](https://attack.mitre.org/software/S0281) downloads and installs [Tor](https://attack.mitre.org/software/S0183) via homebrew.(Citation: objsee ma...
S0687	Cyclops Blink	Malware	[Cyclops Blink](https://attack.mitre.org/software/S0687) has used [Tor](https://attack.mitre.org/software/S0183) nodes for C2 traffic.(Citation: NCSC ...
S1106	NGLite	Malware	[NGLite](https://attack.mitre.org/software/S1106) has abused NKN infrastructure for its C2 communication.(Citation: NGLite Trojan)
S0491	StrongPity	Malware	[StrongPity](https://attack.mitre.org/software/S0491) can use multiple layers of proxy servers to hide terminal nodes in its infrastructure.(Citation:...
S0604	Industroyer	Malware	[Industroyer](https://attack.mitre.org/software/S0604) used [Tor](https://attack.mitre.org/software/S0183) nodes for C2.(Citation: Dragos Crashoverrid...
S0366	WannaCry	Malware	[WannaCry](https://attack.mitre.org/software/S0366) uses [Tor](https://attack.mitre.org/software/S0183) for command and control traffic.(Citation: Sec...
S0384	Dridex	Malware	[Dridex](https://attack.mitre.org/software/S0384) can use multiple layers of proxy servers to hide terminal nodes in its infrastructure.(Citation: Che...

References

Frequently Asked Questions

What is T1090.003 (Multi-hop Proxy)?

T1090.003 is a MITRE ATT&CK technique named 'Multi-hop Proxy'. It belongs to the Command and Control tactic(s). 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 netw...

How can T1090.003 be detected?

Detection of T1090.003 (Multi-hop Proxy) typically involves monitoring system logs, network traffic, and endpoint telemetry. Use SIEM rules, EDR solutions, and behavioral analytics to identify suspicious activity associated with this technique.

What mitigations exist for T1090.003?

There are 1 documented mitigations for T1090.003. Key mitigations include: Filter Network Traffic.

Which threat groups use T1090.003?

Known threat groups using T1090.003 include: Ember Bear, APT28, Inception, Leviathan, FIN4, APT29, Medusa Group, Lotus Blossom.