Malicious PowerShell In-Memory Download Cradle via IEX DownloadString

ATT&CK techniques

Execution → C2

Recon
Resource Dev
Initial Access
Execution
- T1059.001PowerShell
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
Impact

What it detects

This rule detects PowerShell invoking IEX together with a Net.WebClient DownloadString call to fetch and execute code directly in memory. This tradecraft was used by APT41 to stage ShadowPad and Cobalt Strike against a Taiwanese government-affiliated research institute. In-memory download cradles let attackers run remote payloads without writing them to disk which frustrates file-based detection.

Reporting behind it

Related detections9 linkedT1059.001 — drag to rearrange

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Malicious PowerShell IEX DownloadString One-Liner

Malicious Cloud Atlas PowerShell Download Cradle via IEX WebClient (via process_creation)

Suspicious PowerShell Downloader Spawned by Batch Script (via process_creation)

Suspicious Curl Download and Script Execution Chain via Command Line

Malicious PowerShell In-Memory Download Cradle via IEX DownloadString

Pivot detection · T1059.001 · 9 related

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