Potential SharePoint ToolShell CVE-2025-53770 Exploitation - File Create

Description

Detects the creation of file such as spinstall0.aspx which may indicate successful exploitation of CVE-2025-53770. CVE-2025-53770 is a zero-day vulnerability in SharePoint that allows remote code execution.

Query · sigma

selection:
  TargetFilename|startswith:
  - C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\
  - C:\Program Files (x86)\Common Files\Microsoft Shared\Web Server Extensions\
  TargetFilename|contains:
  - \15\TEMPLATE\LAYOUTS\
  - \16\TEMPLATE\LAYOUTS\
  TargetFilename|endswith:
  - \spinstall.aspx
  - \spinstall?.aspx
  - \debug_dev.js
condition: selection

Known false positives

  • Unknown
Raw source Potential SharePoint ToolShell CVE-2025-53770 Exploitation - File Create · Sigma
Esc
Published by SigmaHQ/sigma ↗, licensed under Detection Rule License 1.1 ↗. Reproduced here unmodified. 
title: Potential SharePoint ToolShell CVE-2025-53770 Exploitation - File Create
id: ba479447-721f-42a9-9af2-6dcd517bbdb3
status: experimental
description: |
    Detects the creation of file such as spinstall0.aspx which may indicate successful exploitation of CVE-2025-53770.
    CVE-2025-53770 is a zero-day vulnerability in SharePoint that allows remote code execution.
references:
    - https://research.eye.security/sharepoint-under-siege/
    - https://msrc.microsoft.com/blog/2025/07/customer-guidance-for-sharepoint-vulnerability-cve-2025-53770/
    - https://unit42.paloaltonetworks.com/microsoft-sharepoint-cve-2025-49704-cve-2025-49706-cve-2025-53770/
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-07-21
modified: 2025-07-24
tags:
    - attack.initial-access
    - attack.t1190
    - cve.2025-53770
    - detection.emerging-threats
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|startswith:
            - 'C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\'
            - 'C:\Program Files (x86)\Common Files\Microsoft Shared\Web Server Extensions\'
        TargetFilename|contains:
            - '\15\TEMPLATE\LAYOUTS\'
            - '\16\TEMPLATE\LAYOUTS\'
        TargetFilename|endswith:
            - '\spinstall.aspx'
            - '\spinstall?.aspx'
            - '\debug_dev.js'
    condition: selection
falsepositives:
    - Unknown
level: critical

Detection rules belong to the projects that publish them and remain under their own licenses. This site indexes and links to them; it claims no rights in them.