Adversaries may use an internal proxy to direct command and control traffic between two or more systems in a compromised environment. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap. (Citation: Trend Micro APT Attack Tools) Adversaries use internal proxies to manage command and control communications inside a compromised environment, to reduce the number of simultaneous outbound network connections, to provide resiliency in the face of connection loss, or to ride over existing trusted communications paths between infected systems to avoid suspicion. Internal proxy connections may use common peer-to-peer (p2p) networking protocols, such as SMB, to better blend in with the environment.
By using a compromised internal system as a proxy, adversaries may conceal the true destination of C2 traffic while reducing the need for numerous connections to external systems.
View in MITRE ATT&CK®| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| AC-4 | Information Flow Enforcement | Protects | T1090.001 | Internal Proxy | |
| CA-7 | Continuous Monitoring | Protects | T1090.001 | Internal Proxy | |
| CM-2 | Baseline Configuration | Protects | T1090.001 | Internal Proxy | |
| CM-6 | Configuration Settings | Protects | T1090.001 | Internal Proxy | |
| CM-7 | Least Functionality | Protects | T1090.001 | Internal Proxy | |
| SC-7 | Boundary Protection | Protects | T1090.001 | Internal Proxy | |
| SI-3 | Malicious Code Protection | Protects | T1090.001 | Internal Proxy | |
| SI-4 | System Monitoring | Protects | T1090.001 | Internal Proxy | |
| action.malware.variety.C2 | Command and control (C2) | related-to | T1090.001 | Proxy: Internal Proxy | |
| amazon_guardduty | Amazon GuardDuty | technique_scores | T1090.001 | Internal 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
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| amazon_virtual_private_cloud | Amazon Virtual Private Cloud | technique_scores | T1090.001 | Internal 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
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