Suspicious PowerShell WebClient DownloadFile with Execution Policy Bypass (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 launched with an execution policy bypass and a hidden window that instantiates Net.WebClient to call DownloadFile. This behavior was observed in the updated MATA campaign against industrial companies to stage additional payloads onto compromised hosts. Detecting this scripted download surfaces the ingress-tool-transfer stage of the intrusion.

Reporting behind it

Related detections9 linkedT1059.001 — drag to rearrange

Malicious ActiveMQ Exploitation Java Spawning PowerShell Downloader (via process_creation)

Malicious In-Memory Payload Execution via PowerShell DownloadString (via process_creation)

Suspicious Remote Script Download and Execution via iwr Piped to iex

Suspicious PowerShell Invoke-WebRequest Download of Executable Payload

Suspicious Hidden PowerShell Download and Archive Expansion

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

Suspicious PowerShell WebClient DownloadFile with Execution Policy Bypass (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.

Full detection rule

Unlock this rule to view and copy it

The detection logic is included with a plan. Everything else — context, mappings and implementation details — stays free on this page.

Sign in for 3 free unlocks

Signing in gives you 3 unlocks to spend on any rule in the library. No card, and they do not expire.

Also included

Unlocked rules convert on this page — to Splunk SPL or Splunk — Raw Index SPL or Microsoft Sentinel KQL or Microsoft Sentinel ASIM ASIM KQL or Microsoft Defender XDR KQL or Elastic Security KQL or Elastic Security Lucene or Elastic Security ES|QL or CrowdStrike Falcon CQL or SentinelOne PowerQuery or Palo Alto Cortex XDR XQL or Carbon Black Cloud Platform Search or Carbon Black EDR Process Search or Google Security Operations UDM Search or IBM QRadar AQL or Sumo Logic Cloud SIEM Rules expression or Rapid7 InsightIDR LEQL or Graylog Search or OpenSearch Lucene or OpenSearch PPL PPL or Grafana Loki LogQL or SQLite SQL or Zircolite SQLite — with the log-source profile the engine picked, the field map it used, and everything it could not express. Converting a rule you have unlocked costs no further credit.

See it run on a free rule →Convert your own rule →