T1090
Proxy
ESXi · Linux · macOS · Network Devices · Windowsnothing on this site yetT1090 on attack.mitre.org
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. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap.
how MITRE says to see it
Detection of Proxy Infrastructure Setup and Traffic Bridging
- Suspicious process spawning (e.g., `rundll32`, `svchost`, `powershell`, or `netsh`) followed by network connection creation to internal hosts or uncommon external endpoints on high or non-standard ports.
- User-space tools (e.g., `socat`, `ncat`, `iptables`, `ssh`) used in non-standard ways to establish reverse shells, port-forwarding, or inter-host connections. Often chained with uncommon outbound destinations or SSH tunnels.
- AppleScript, LaunchAgents, or remote login services (`ssh`, `networksetup`) establishing proxy tunnels or dynamic port forwards to external IPs or alternate local hosts.
- Direct use of `nc`, `socat`, or reverse tunnel scripts initiated by abnormal user contexts or unauthorized VIBs initiating connections from hypervisor to external systems.
what reduces it
- M1031 Network Intrusion Prevention. 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. Signatures are often for unique indicators within protocols and may be based on the specific C2 protocol used by a particular adversary or tool, and will likely be different across various malware families and versions.
- M1037 Filter Network Traffic. Traffic to known anonymity networks and C2 infrastructure can be blocked through the use of network allow and block lists. It should be noted that this kind of blocking may be circumvented by other techniques like Domain Fronting.
- M1020 SSL/TLS Inspection. If it is possible to inspect HTTPS traffic, the captures can be analyzed for connections that appear to be domain fronting.