Malicious Web Shell Written to SharePoint LAYOUTS Directory by Worker Process (via file_event)

ATT&CK techniques

Initial Access → Persistence

Recon
Resource Dev
Initial Access
- T1190Exploit Public-Facing Application
Execution
Persistence
- T1505.003Web Shell
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects the SharePoint IIS worker process writing an ASPX file into the LAYOUTS template directory. ToolShell exploitation dropped web shells such as spinstall0.aspx into this path to steal ASP.NET machine keys and maintain credential less access. Web shell files are not created here during normal SharePoint use.

Reporting behind it

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Malicious Web Shell Written to SharePoint LAYOUTS Directory by Worker Process (via file_event)

Pivot detection · T1190 · 9 related

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