Suspicious PowerShell Download Cradle via IEX and DownloadString (via process_creation)

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 Invoke-Expression against the output of a DownloadString call. Rapid7 observed this in-memory download cradle in the exposed WebDAV malware delivery lab to fetch and execute remote script content without touching disk. Combining a remote download with immediate execution is a hallmark of fileless payload delivery.

Reporting behind it

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Suspicious PowerShell Download Cradle via Invoke-WebRequest Piped to iex (via process_creation)

Suspicious PowerShell Download Cradle via IEX and DownloadString (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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