huntrule

Suspicious ToolShell Webshell Written to SharePoint Layouts Directory

PremiumReviewedSigma · High · v1
Product
windows
Category
file_event
Author
HuntRule
Published
2026-09-23
Updated
2026-09-23
AnalysisDetection

ATT&CK techniques

Persistence

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule detects creation of the ToolShell webshell files spinstall0.aspx or ghostfile-prefixed .aspx files used by multiple threat actors after exploiting the SharePoint ToolShell vulnerability chain. These named ASPX payloads dropped onto a SharePoint server provide persistent remote command execution and are strong indicators of compromise.

Reporting behind it

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Suspicious ToolShell Webshell Written to SharePoint Layouts Directory
Pivot detection · T1505.003 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.