Suspicious China Chopper Web Shell in Temporary ASP.NET Files
- Product
- windows
- Category
- file_event
- Author
- HuntRule
- Published
- 2026-06-10
- 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 compiled App_Web assemblies written into the Temporary ASP.NET Files directory, the artifact left when Tropic Trooper's China Chopper web shell embedded in an Umbraco page is compiled by IIS. While ASP.NET compiles legitimate pages here too, unexpected App_Web DLLs on a static or CMS server warrant review for web shell activity.
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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