Suspicious PowerShell Hidden Web Download via Invoke-WebRequest by CatB Ransomware

ATT&CK techniques

C2

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

What it detects

This rule detects a hidden PowerShell or cmd invocation combining Invoke-WebRequest with DownloadData to retrieve a payload, matching the ingress tool transfer behavior emulated for CatB ransomware. Running the download in a hidden window is a common defense evasion tactic for staging follow-on malware.

Reporting behind it

Related detections9 linkedT1105 — drag to rearrange

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

Suspicious Remote File Download via certutil URLCache (via process_creation)

Suspicious WebDAV Retrieval via rundll32 and davclnt.dll (via process_creation)

Suspicious PowerShell Download to Temp and In-Memory Execution via IEX (via process_creation)

Suspicious PowerShell Download of Bumblebee Stager Files (via process_creation)

Suspicious PowerShell Hidden Web Download via Invoke-WebRequest by CatB Ransomware

Pivot detection · T1105 · 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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