Windows Security: Password-Protected ZIP Opened with Suspicious Filename Indicators

Alerts when Windows opens password-protected ZIP contents with filenames commonly tied to invoices, orders, payments, and deliveries.

FreeReviewedSigma · High · v2

Product: windows
Service: security
Author: Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2022-05-09
Updated: 2026-07-31

Analysis Detection

ATT&CK techniques

Defense Evasion → C2

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1027Obfuscated Files or Information
- T1036Masquerading
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
Impact

What it detects

This rule matches Windows Security EventID 5379 events indicating a password-protected ZIP archive was opened. It further filters for opened ZIP contents whose target filename contains terms commonly associated with business document lures (e.g., invoice, order, payment). This behavior can help attackers deliver or conceal malicious payloads using encrypted archives and socially relevant filenames, relying on event telemetry that includes the ZIP folder target filename.

Reporting behind it

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Windows Security: Password-Protected ZIP Opened with Suspicious Filename Indicators

Pivot detection · T1105 · 9 related

Changelog

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-security-opened-encrypted-zip-files-with-suspicious-invoice-order-filena-54f0434b

title: "Windows Security: Password-Protected ZIP Opened with Suspicious Filename Indicators"
id: 5bed0aec-d052-47ff-ae96-e40c057fe63b
status: test
description: This rule matches Windows Security EventID 5379 events indicating a password-protected ZIP archive was opened. It further filters for opened ZIP contents whose target filename contains terms commonly associated with business document lures (e.g., invoice, order, payment). This behavior can help attackers deliver or conceal malicious payloads using encrypted archives and socially relevant filenames, relying on event telemetry that includes the ZIP folder target filename.
references:
  - https://twitter.com/sbousseaden/status/1523383197513379841
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/security/win_security_susp_opened_encrypted_zip_filename.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2022-05-09
tags:
  - attack.command-and-control
  - attack.stealth
  - attack.t1027
  - attack.t1105
  - attack.t1036
logsource:
  product: windows
  service: security
detection:
  selection:
    EventID: 5379
    TargetName|contains: Microsoft_Windows_Shell_ZipFolder:filename
  selection_filename:
    TargetName|contains:
      - invoice
      - new order
      - rechnung
      - factura
      - delivery
      - purchase
      - order
      - payment
  condition: selection and selection_filename
falsepositives:
  - Legitimate used of encrypted ZIP files
level: high
license: DRL-1.1
related:
  - id: 54f0434b-726f-48a1-b2aa-067df14516e4
    type: derived

Convert

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