T1090.003 Multi-hop Proxy Mappings

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)

View in MITRE ATT&CK®

VERIS Mappings

Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
action.malware.variety.Backdoor or C2 Malware creates a remote control capability, but it's unclear if it's a backdoor for hacking or C2 for malware. Parent of 'C2' and 'Backdoor'. related-to T1090.003 Proxy: Multi-hop Proxy
action.malware.variety.C2 Malware creates Command and Control capability for malware. Child of 'Backdoor or C2'. related-to T1090.003 Proxy: Multi-hop Proxy

AWS Mappings

Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
amazon_guardduty Amazon GuardDuty technique_scores T1090.003 Multi-hop Proxy
Comments
The UnauthorizedAccess:EC2/TorClient GuardDuty finding type flags events where adversaries may use a connection proxy to direct network traffic between systems or act as an intermediary for network communications to a command-and-control server to avoid direct connections to their infrastructure. Due to the detection being limited to a specific type of proxy, Tor, its coverage is Minimal resulting in a Minimal score.
References
    amazon_virtual_private_cloud Amazon Virtual Private Cloud technique_scores T1090.003 Multi-hop Proxy
    Comments
    VPC security groups and network access control lists (NACLs) can restrict access between systems, enclaves, and workloads thereby mitigating these proxy related sub-techniques.
    References
      aws_network_firewall AWS Network Firewall technique_scores T1090.003 Multi-hop Proxy
      Comments
      AWS Network Firewall has the ability to pass, drop, or alert on traffic based on the network protocol as well as perform deep packet inspection on the payload. This functionality can be used to block traffic from known bad IP addresses and to known bad domains that serve as proxies for adversaries. This mapping is given a score of partial because it only blocks known bad IP addresses and domains and does not protect against unknown ones.
      References
        aws_web_application_firewall AWS Web Application Firewall technique_scores T1090.003 Multi-hop Proxy
        Comments
        The AWS WAF protects web applications from access by adversaries that leverage tools that obscure their identity (e.g., VPN, proxies, Tor, hosting providers). AWS WAF provides this protection via the following rule set that blocks incoming traffic from IP addresses known to anonymize connection information or be less likely to source end user traffic. AWSManagedRulesAnonymousIpList This is given a score of Partial because it provide protections based only on known IP addresses. Furthermore, it blocks the malicious content in near real-time.
        References