T1090.002 External Proxy Mappings

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®

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 T1090.002 Proxy: External Proxy
action.malware.variety.C2 Malware creates Command and Control capability for malware. Child of 'Backdoor or C2'. related-to T1090.002 Proxy: External Proxy

AWS Mappings

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.
References
    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.
    References
      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.
      References
        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.
        References