IIS Web Logs: SharePoint ToolPane and spinstall0.aspx CVE-2025-53770 Exploitation Indicators

Alerts on IIS log traffic to SharePoint ToolPane/spinstall0 endpoints with a SignOut referer, matching indicators for CVE-2025-53770 exploitation.

FreeReviewedSigma · Medium · v5
Category
webserver
Author
Swachchhanda Shrawan Poudel (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2025-07-21
Updated
2026-07-31
title: "IIS Web Logs: SharePoint ToolPane and spinstall0.aspx CVE-2025-53770 Exploitation Indicators"
id: faba7e81-80d2-4cd9-a759-7cd728f8ffab
status: experimental
description: This rule flags IIS web requests consistent with exploitation attempts targeting SharePoint endpoints. It matches POST traffic to /_layouts/15/ToolPane.aspx with a DisplayMode=Edit query and GET traffic to /_layouts/15/spinstall0.aspx, combined with a referer containing /_layouts/SignOut.aspx. The detection relies on web server log fields for HTTP method, URI stem, query string content, and HTTP referrer.
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/
  - https://github.com/SigmaHQ/sigma/blob/master/rules-emerging-threats/2025/Exploits/CVE-2025-53770/web_win_iis_exploit_cve_2025_53770.yml
author: Swachchhanda Shrawan Poudel (Nextron Systems), Huntrule Team
date: 2025-07-21
tags:
  - attack.initial-access
  - attack.t1190
  - cve.2025-53770
  - detection.emerging-threats
logsource:
  category: webserver
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
license: DRL-1.1
related:
  - id: 48d053db-6a56-4866-b60d-0975647050ed
    type: derived