Detect Hidden Window in Elastic Security
Adversaries may use hidden windows to conceal malicious activity from users. On Windows, this is achieved through PowerShell's -WindowStyle Hidden flag or by using the ShowWindow API with SW_HIDE. The CreateProcess API's STARTUPINFO structure also allows processes to be created without a visible window. On macOS, the LSUIElement or LSBackgroundOnly Info.plist keys make applications background-only. Malware families using hidden windows include Astaroth, QuietSieve, StrongPity, and LockBit 2.0.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1564 Hide Artifacts
- Sub-technique
- T1564.003 Hidden Window
- Canonical reference
- https://attack.mitre.org/techniques/T1564/003/
Elastic Detection Query
process where event.type == "start"
and process.name in~ ("powershell.exe", "pwsh.exe", "cmd.exe", "wscript.exe", "cscript.exe")
and (
process.args : ("-WindowStyle", "-w", "-windowstyle") and process.args : ("Hidden", "hidden", "h")
or process.command_line : ("*-WindowStyle Hidden*", "*-w hidden*", "*-windowstyle h*", "*/hh*")
or (process.command_line : ("*-NonInteractive*", "*-noni*", "*-NonI*") and process.command_line : ("*-WindowStyle*", "*-w *"))
)Detects processes launched with hidden window flags including PowerShell -WindowStyle Hidden and cmd /hh. Correlates with encoded commands, download cradles, and execution policy bypass for risk scoring.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate administrative scripts run silently via task scheduler or deployment tools (SCCM, Ansible) that use -WindowStyle Hidden to avoid UI pop-ups
- Software installers and update agents (e.g., Windows Update, Chrome updater) that spawn hidden PowerShell processes during patching
- Security tooling and EDR agents that use hidden PowerShell for telemetry collection or remediation actions
Other platforms for T1564.003
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1PowerShell Hidden Window Execution
Expected signal: Sysmon Event ID 1: powershell.exe with -WindowStyle Hidden in command line. Sysmon Event ID 11: file created at Temp path. PowerShell ScriptBlock Log Event ID 4104 with the command content.
- Test 2Hidden Window with Encoded Command
Expected signal: Sysmon Event ID 1: powershell.exe with both -WindowStyle Hidden and -EncodedCommand in command line. PowerShell ScriptBlock Log Event ID 4104 showing decoded content 'whoami'.
- Test 3Hidden Window with Execution Policy Bypass and Download Cradle
Expected signal: Sysmon Event ID 1: powershell.exe with all three flags. Sysmon Event ID 3: network connection attempt to 127.0.0.1:8080. The download will fail (no server) but both process creation and network events fire.
References (4)
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