Windows: WinRAR/Rar.exe Writing Files to Startup Folder Locations
Alerts on WinRAR/Rar creating files under the Windows Startup folder, a common persistence attempt.
- Product
- windows
- Category
- file_event
- Author
- Swachchhanda Shrawan Poudel (Nextron Systems) (SigmaHQ), DRL 1.1
- Published
- 2025-07-16
- Updated
- 2026-07-31
ATT&CK techniques
Persistence → Priv EscRecon
Resource Dev
Initial Access
Execution
Persistence
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule identifies WinRAR or Rar executing while creating/writing a file whose path contains the Windows Startup directory under the Start Menu Programs. Malicious use of Startup folders can provide persistence by launching attacker-controlled files when a user logs in. Detection relies on Windows file event telemetry that records the creating process image and the target filename/path.
Reporting behind it
- github.comhttps://github.com/mulwareX/CVE-2025-6218-POC
- x.comhttps://x.com/0x534c/status/1944694507787710685
- welivesecurity.comhttps://www.welivesecurity.com/en/eset-research/update-winrar-tools-now-romcom-and-others-exploiting-zero-day-vulnerability/
- github.comhttps://github.com/SigmaHQ/sigma/blob/master/rules/windows/file/file_event/file_event_win_winrar_file_creation_in_startup_folder.yml
Changelog
v2- v2Candidate ingested via manual entry.2026-07-31
- v1No 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.
title: "Windows: WinRAR/Rar.exe Writing Files to Startup Folder Locations"
id: 3b37b5d0-2353-419b-b1e3-d7e371c6dcfc
status: experimental
description: This rule identifies WinRAR or Rar executing while creating/writing a file whose path contains the Windows Startup directory under the Start Menu Programs. Malicious use of Startup folders can provide persistence by launching attacker-controlled files when a user logs in. Detection relies on Windows file event telemetry that records the creating process image and the target filename/path.
references:
- https://github.com/mulwareX/CVE-2025-6218-POC
- https://x.com/0x534c/status/1944694507787710685
- https://www.welivesecurity.com/en/eset-research/update-winrar-tools-now-romcom-and-others-exploiting-zero-day-vulnerability/
- https://github.com/SigmaHQ/sigma/blob/master/rules/windows/file/file_event/file_event_win_winrar_file_creation_in_startup_folder.yml
author: Swachchhanda Shrawan Poudel (Nextron Systems), Huntrule Team
date: 2025-07-16
tags:
- attack.privilege-escalation
- attack.persistence
- attack.t1547.001
logsource:
category: file_event
product: windows
detection:
selection:
Image|endswith:
- \WinRAR.exe
- \Rar.exe
TargetFilename|contains: \Start Menu\Programs\Startup\
condition: selection
falsepositives:
- Unknown
level: high
license: DRL-1.1
related:
- id: 74a2b37d-fea4-41e0-9ac7-c9fbcf1f60cc
type: derived