title: SharePoint ToolShell CVE-2025-53770 Exploitation - Web IIS
id: 48d053db-6a56-4866-b60d-0975647050ed
status: experimental
description: |
    Detects access to vulnerable SharePoint components potentially being exploited in CVE-2025-53770 through IIS web server logs.
    CVE-2025-53770 is a zero-day vulnerability in SharePoint that allows remote code execution.
references:
    - https://www.linkedin.com/posts/mauricefielenbach_sharepoint-incidentresponse-windowssecurity-activity-7352653907363303425-bL2f
    - https://research.eye.security/sharepoint-under-siege/
    - https://msrc.microsoft.com/blog/2025/07/customer-guidance-for-sharepoint-vulnerability-cve-2025-53770/
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-07-21
tags:
    - attack.initial-access
    - attack.t1190
    - cve.2025-53770
    - detection.emerging-threats
logsource:
    category: webserver # IIS web server logs
detection:
    selection_exploit_post:
        cs-method: 'POST'
        cs-uri-stem|contains: '/_layouts/15/ToolPane.aspx'
        cs-uri-query|contains: 'DisplayMode=Edit&a=/ToolPane.aspx'
    selection_exploit_get:
        cs-method: 'GET'
        cs-uri-stem|contains: '/_layouts/15/spinstall0.aspx'
    selection_referer:
        cs-referer|contains: '/_layouts/SignOut.aspx'
    condition: 1 of selection_exploit_* and selection_referer
falsepositives:
    - Unknown
level: medium