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DET0081 Detection of Proxy Execution via Trusted Signed Binaries Across Platforms

Item Value
ID DET0081
Version 1.0
Created 21 October 2025
Last Modified 21 October 2025

Technique Detected: T1218 (System Binary Proxy Execution)

Analytics

Windows

AN0226

Execution of trusted, Microsoft-signed binaries such as rundll32.exe, msiexec.exe, or regsvr32.exe used to execute externally hosted, unsigned, or suspicious payloads through command-line parameters or network retrieval.

Log Sources
Data Component Name Channel
Process Creation (DC0032) WinEventLog:Sysmon EventCode=1
Network Connection Creation (DC0082) WinEventLog:Sysmon EventCode=3, 22
Module Load (DC0016) WinEventLog:Sysmon EventCode=7
Mutable Elements
Field Description
ParentProcessName Used to profile unexpected parent-child relationships (e.g., regsvr32.exe not launched by explorer.exe)
SignedBinaryList List of known signed binaries allowed for execution (e.g., msiexec.exe, regsvr32.exe)
CommandLineRegex Regex to match suspicious arguments, such as URLs, script paths, or DLL entrypoints
RemoteDomainAllowlist Filter to suppress activity contacting legitimate enterprise domains

Linux

AN0227

Execution of trusted system binaries (e.g., split, tee, bash, env) used in uncommon sequences or chained behaviors to execute malicious payloads or perform actions inconsistent with normal system or script behavior.

Log Sources
Data Component Name Channel
Process Creation (DC0032) auditd:SYSCALL execve
Network Connection Creation (DC0082) auditd:SYSCALL connect
Mutable Elements
Field Description
TrustedBinaryList Binaries like split, tee, env, awk, gzip, often used in benign scripts
AnomalyScore Outlier model for process tree and command arguments

macOS

AN0228

Use of system binaries such as osascript, bash, or curl to download or execute unsigned code or files in conjunction with application proxying.

Log Sources
Data Component Name Channel
Process Creation (DC0032) macos:unifiedlog exec of osascript, bash, curl with suspicious parameters
Network Connection Creation (DC0082) macos:osquery execution of trusted tools interacting with external endpoints
Mutable Elements
Field Description
TrustedUtilityList macOS binary whitelist including /usr/bin/osascript, /bin/bash, /usr/bin/curl
SignedToUnsignedTransition Used to detect proxy execution from signed binary to unsigned payload