Windows Process: Squirrel.exe Using Download/Update Flags to Fetch Files
Alert on Squirrel.exe/update.exe runs with --download/--update flags and HTTP in the command line.
- Product
- windows
- Category
- process_creation
- Author
- Nasreddine Bencherchali (Nextron Systems), Karneades / Markus Neis, Jonhnathan Ribeiro, oscd.community (SigmaHQ), DRL 1.1
- Published
- 2022-06-09
- Updated
- 2026-07-30
ATT&CK techniques
Defense EvasionRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule flags Windows process executions where the image path ends with Squirrel.exe or update.exe and the command line includes Squirrel download or update parameters. Attackers can abuse Squirrel.exe, commonly present with Electron-based applications, to retrieve arbitrary external content through automated download/update workflows. The detection relies on process creation telemetry, specifically the executable name and command-line arguments, including HTTP presence.
Reporting behind it
- lolbas-project.github.iohttps://lolbas-project.github.io/lolbas/OtherMSBinaries/Squirrel/
- hexacorn.comhttp://www.hexacorn.com/blog/2019/03/30/sqirrel-packages-manager-as-a-lolbin-a-k-a-many-electron-apps-are-lolbins-by-default/
- hexacorn.comhttp://www.hexacorn.com/blog/2018/08/16/squirrel-as-a-lolbin/
- github.comhttps://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_squirrel_download.yml
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
title: "Windows Process: Squirrel.exe Using Download/Update Flags to Fetch Files"
id: 1c379257-fbad-41ba-a63c-0374a4ee0534
related:
- id: 45239e6a-b035-4aaf-b339-8ad379fcb67e
type: similar
- id: fa4b21c9-0057-4493-b289-2556416ae4d7
type: obsolete
- id: 1e75c1cc-c5d4-42aa-ac3d-91b0b68b3b4c
type: derived
status: test
description: This rule flags Windows process executions where the image path ends with Squirrel.exe or update.exe and the command line includes Squirrel download or update parameters. Attackers can abuse Squirrel.exe, commonly present with Electron-based applications, to retrieve arbitrary external content through automated download/update workflows. The detection relies on process creation telemetry, specifically the executable name and command-line arguments, including HTTP presence.
references:
- https://lolbas-project.github.io/lolbas/OtherMSBinaries/Squirrel/
- http://www.hexacorn.com/blog/2019/03/30/sqirrel-packages-manager-as-a-lolbin-a-k-a-many-electron-apps-are-lolbins-by-default/
- http://www.hexacorn.com/blog/2018/08/16/squirrel-as-a-lolbin/
- https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_squirrel_download.yml
author: Nasreddine Bencherchali (Nextron Systems), Karneades / Markus Neis, Jonhnathan Ribeiro, oscd.community, Huntrule Team
date: 2022-06-09
modified: 2023-11-09
tags:
- attack.execution
- attack.stealth
- attack.t1218
logsource:
category: process_creation
product: windows
detection:
selection_img:
Image|endswith:
- \squirrel.exe
- \update.exe
selection_download_cli:
CommandLine|contains:
- " --download "
- " --update "
- " --updateRollback="
selection_download_http_keyword:
CommandLine|contains: http
condition: all of selection_*
falsepositives:
- Expected FP with some Electron based applications such as (1Clipboard, Beaker Browser, Caret, Discord, GitHub Desktop, etc.)
level: medium
license: DRL-1.1