Windows SharePoint Spinstall0 GET Request

The following analytic detects potential post-exploitation activity related to the Microsoft SharePoint CVE-2025-53770 vulnerability. After successful exploitation via the ToolPane.aspx endpoint, attackers typically deploy a webshell named "spinstall0.aspx" in the SharePoint layouts directory. This detection identifies GET requests to this webshell, which indicates active use of the backdoor for command execution, data exfiltration, or credential/key extraction. Attackers commonly use these webshells to extract encryption keys, authentication tokens, and other sensitive information from the compromised SharePoint server.