Windows Process Creation: Detects Command-Line Ending With '.exe Platypus'

Alerts when a Windows process command line ends with '.exe Platypus', matching a Small Sieve indicator.

FreeReviewedSigma · High · v5

Product: windows
Category: process_creation
Author: Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2023-05-19
Updated: 2026-07-31

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1574.001DLL
Persistence
- T1574.001DLL
Priv Esc
- T1574.001DLL
Defense Evasion
- T1574.001DLL
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags Windows process creation events where the command line ends with the pattern '.exe Platypus'. Attackers may use crafted command-line arguments to execute or steer malicious components, so exact command-line matching can help surface suspicious execution. It relies on process creation telemetry that includes the full command line string for running processes.

Reporting behind it

Related detections9 linkedT1574.001 — drag to rearrange

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Windows Process Creation: Detects Command-Line Ending With '.exe Platypus'

Pivot detection · T1574.001 · 9 related

Changelog

v5
Candidate ingested via manual entry.2026-07-31
v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

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

windows-process-creation-commandline-ends-with-exe-platypus-indicator-21117127

title: "Windows Process Creation: Detects Command-Line Ending With '.exe Platypus'"
id: 9b8b7c97-7487-4099-b353-aaa8c5ecffad
status: test
description: This rule flags Windows process creation events where the command line ends with the pattern '.exe Platypus'. Attackers may use crafted command-line arguments to execute or steer malicious components, so exact command-line matching can help surface suspicious execution. It relies on process creation telemetry that includes the full command line string for running processes.
references:
  - https://www.ncsc.gov.uk/static-assets/documents/malware-analysis-reports/small-sieve/NCSC-MAR-Small-Sieve.pdf
  - https://github.com/SigmaHQ/sigma/blob/master/rules-emerging-threats/2021/Malware/Small-Sieve/proc_creation_win_malware_small_sieve_cli_arg.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2023-05-19
tags:
  - attack.privilege-escalation
  - attack.persistence
  - attack.execution
  - attack.stealth
  - attack.t1574.001
  - detection.emerging-threats
logsource:
  product: windows
  category: process_creation
detection:
  selection:
    CommandLine|endswith: .exe Platypus
  condition: selection
falsepositives:
  - Unlikely
level: high
license: DRL-1.1
related:
  - id: 21117127-21c8-437a-ae03-4b51e5a8a088
    type: derived

Convert

This rule as a query you can run. Uses no unlock credit.

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