Sub-technique of T1090 Proxy.View on attack.mitre.org
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. 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.
Rules on DetectionCode tagged with T1090.002.
| Rule | Level | Log source |
|---|---|---|
| RDP over Reverse SSH Tunnel WFP | high | windows / NULL |
| Network Communication Initiated To Portmap.IO Domain | medium | windows / network_connection |
| Rule | Type | Risk | Data source |
|---|---|---|---|
| Cisco Secure Firewall - Connection to File Sharing Domain | Anomaly | NULL | Cisco Secure Firewall Threat Defense Connection Event |
| Used by | Procedure example |
|---|---|
| GroupAPT28 | APT28 used other victims as proxies to relay command traffic, for instance using a compromised Georgian military email server as a hop point to NATO victims. The group has also used a tool that acts as a proxy to allow C2 even if the victim is behind a router. APT28 has also used a machine to relay and obscure communications between CHOPSTICK and their server. |
| GroupAPT29 | APT29 uses compromised residential endpoints as proxies for defense evasion and network access. |
| GroupAPT3 | An APT3 downloader establishes SOCKS5 connections for its initial C2. |
| GroupAPT39 | APT39 has used various tools to proxy C2 communications. |
| GroupFIN5 | FIN5 maintains access to victim environments by using FLIPSIDE to create a proxy for a backup RDP tunnel. |
| GroupGALLIUM | GALLIUM used a modified version of HTRAN to redirect connections between networks. |
| GroupLazarus Group | Lazarus Group has used multiple proxies to obfuscate network traffic from victims. |
| GroupmenuPass | menuPass has used a global service provider's IP as a proxy for C2 traffic from a victim. |
| Used by | Procedure example |
|---|---|
| Toolevilginx2 | evilginx2 can route traffic via SOCKS5 and HTTP(S) proxies between an intended phishing victim's machine and legitimate websites. |
| MalwareInvisiMole | InvisiMole InvisiMole can identify proxy servers used by the victim and use them for C2 communication. |
| ToolMythic | Mythic can leverage a modified SOCKS5 proxy to tunnel egress C2 traffic. |
| MalwareOkrum | Okrum can identify proxy servers configured and used by the victim, and use it to make HTTP requests to C2 its server. |
| MalwarePOWERSTATS | POWERSTATS has connected to C2 servers through proxies. |
| MalwareQakBot | QakBot has a module that can proxy C2 communications. |
| MalwareQUIETEXIT | QUIETEXIT can proxy traffic via SOCKS. |
| MalwareRegin | Regin leveraged several compromised universities as proxies to obscure its origin. |
| Used by | Procedure example |
|---|---|
| CampaignQuad7 Activity | Quad7 Activity has initialized SOCKS5 proxies on compromised devices. |
Data from MITRE ATT&CK® (Enterprise). ATT&CK® is a registered trademark of The MITRE Corporation.
