Suspicious Process Proxy Execution Through Squirrel.EXE (via process_creation)

title: Suspicious Process Proxy Execution Through Squirrel.EXE (via process_creation)
id: 4a9ecfc1-ab25-570f-b0c3-342ba78beb0f
status: stable
description: This rule detects the use of the "Squirrel.exe" binary to execute arbitrary processes. This binary is part of multiple Electron based software installations (Slack, Teams, Discord, etc.)
references:
    - https://attack.mitre.org/techniques/T1218/
    - 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/
author: Huntrule Team
date: 2026-06-03
tags:
    - attack.execution
    - attack.stealth
    - attack.t1218
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        Image|endswith:
            - '\squirrel.exe'
            - '\update.exe'
    selection_exec:
        CommandLine|contains:
            - '--processStart'
            - '--processStartAndWait'
            - '--createShortcut'
    filter_optional_discord:
        CommandLine|contains|all:
            - ':\Users\'
            - '\AppData\Local\Discord\Update.exe'
            - 'Discord.exe'
        CommandLine|contains:
            - '--createShortcut'
            - '--processStart'
    filter_optional_github_desktop:
        CommandLine|contains|all:
            - ':\Users\'
            - '\AppData\Local\GitHubDesktop\Update.exe'
            - 'GitHubDesktop.exe'
        CommandLine|contains:
            - '--createShortcut'
            - '--processStartAndWait'
    filter_optional_teams:
        CommandLine|contains|all:
            - ':\Users\'
            - '\AppData\Local\Microsoft\Teams\Update.exe'
            - 'Teams.exe'
        CommandLine|contains:
            - '--processStart'
            - '--createShortcut'
    filter_optional_yammer:
        CommandLine|contains|all:
            - ':\Users\'
            - '\AppData\Local\yammerdesktop\Update.exe'
            - 'Yammer.exe'
        CommandLine|contains:
            - '--processStart'
            - '--createShortcut'
    filter_hr:
        CommandLine|contains: Slack.exe
    condition: (all of selection_* and not 1 of filter_optional_*) and not filter_hr
falsepositives:
    - Unknown
level: medium