Suspicious Encoded PowerShell with Hidden Window via Process Creation

ATT&CK techniques

Execution

Recon
Resource Dev
Initial Access
Execution
- T1059.001PowerShell
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects PowerShell invoked with a base64-encoded command while suppressing its window, the launcher behavior of the UAC-0099 LonePage VBS chain that decodes and runs a hidden beacon. Combining encoded payloads with a hidden window is a strong indicator of covert script execution rather than administrative use.

Reporting behind it

Related detections9 linkedT1059.001 — drag to rearrange

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Malicious ActiveMQ Exploitation Java Spawning PowerShell Downloader (via process_creation)

Suspicious Cleo Autorun Health Check File Drop (via file_event)

Suspicious PowerShell Spawned by VBScript for RMM Delivery

Suspicious PowerShell Loading Fake Edge Update Script

Suspicious Encoded PowerShell with Hidden Window via Process Creation

Pivot detection · T1059.001 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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