Adversaries may use an external proxy to act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure. 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 these types of proxies to manage command and control communications, to provide resiliency in the face of connection loss, or to ride over existing trusted communications paths to avoid suspicion.
External connection proxies are used to mask the destination of C2 traffic and are typically implemented with port redirectors. Compromised systems outside of the victim environment may be used for these purposes, as well as purchased infrastructure such as cloud-based resources or virtual private servers. Proxies may be chosen based on the low likelihood that a connection to them from a compromised system would be investigated. Victim systems would communicate directly with the external proxy on the Internet and then the proxy would forward communications to the C2 server.
View in MITRE ATT&CK®| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| DE.AE-02.01 | Event analysis and detection | Mitigates | T1090.002 | External Proxy |
Comments
This diagnostic statement provides for implementation of methods to block similar future attacks via security tools such as antivirus and IDS/IPS to provide protection against threats and exploitation attempts.
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| DE.CM-01.01 | Intrusion detection and prevention | Mitigates | T1090.002 | External Proxy |
Comments
This diagnostic statement protects adversaries from infiltrating external proxies and taking over control of traffic between systems. 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.
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| PR.IR-01.03 | Network communications integrity and availability | Mitigates | T1090.002 | External Proxy |
Comments
This diagnostic statement protects against External Proxy through the use of secure network configurations, architecture, implementations of zero trust architecture, and segmentation.
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| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| CA-07 | Continuous Monitoring | mitigates | T1090.002 | External Proxy | |
| CM-06 | Configuration Settings | mitigates | T1090.002 | External Proxy | |
| SI-03 | Malicious Code Protection | mitigates | T1090.002 | External Proxy | |
| CM-02 | Baseline Configuration | mitigates | T1090.002 | External Proxy | |
| CM-07 | Least Functionality | mitigates | T1090.002 | External Proxy | |
| SI-04 | System Monitoring | mitigates | T1090.002 | External Proxy | |
| AC-04 | Information Flow Enforcement | mitigates | T1090.002 | External Proxy | |
| SC-07 | Boundary Protection | mitigates | T1090.002 | External Proxy |
| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| action.hacking.vector.Web application | Web application | related-to | T1090.002 | External Proxy | |
| action.malware.variety.Capture app data | Capture data from application or system process | related-to | T1090.002 | External Proxy |
| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| azure_network_security_groups | Azure Network Security Groups | technique_scores | T1090.002 | External Proxy |
Comments
This control can restrict access between systems, enclaves, and workloads thereby mitigating these proxy related sub-techniques.
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| azure_network_watcher_traffic_analytics | Azure Network Watcher: Traffic Analytics | technique_scores | T1090.002 | External Proxy |
Comments
This control can detect abuse of external proxies.
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| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| amazon_guardduty | Amazon GuardDuty | technique_scores | T1090.002 | External 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.
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| amazon_virtual_private_cloud | Amazon Virtual Private Cloud | technique_scores | T1090.002 | External 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.
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| aws_network_firewall | AWS Network Firewall | technique_scores | T1090.002 | External 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.
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| aws_web_application_firewall | AWS Web Application Firewall | technique_scores | T1090.002 | External 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.
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