Malicious SharePoint spinstall Web Shell Access Leaking Machine Keys
- Category
- webserver
- Author
- HuntRule
- Published
- 2026-06-11
- Updated
- 2026-08-28
ATT&CK techniques
PersistenceRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule detects web requests to the spinstall web shell dropped during on-premises SharePoint exploitation. Microsoft observed spinstall0.aspx and its variants deployed to leak the server MachineKey via GET requests. Retrieval of the ASP.NET machine key enables forged payloads and full compromise, so any access to this web shell is a critical finding.
Reporting behind it
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
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