Malicious China Chopper Web Shell Command Pattern in IIS Worker Process (via process_creation)

ATT&CK techniques

Execution → Persistence

Recon
Resource Dev
Initial Access
Execution
- T1059Command and Scripting Interpreter
Persistence
- T1505.003Web Shell
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects the China Chopper web shell command marker &cd&echo in commands run by the IIS worker process, a hallmark of the web shells deployed against on-premises Exchange and SharePoint servers in these attacks. Adversaries use China Chopper to execute arbitrary commands through a compromised web application, so this distinctive command wrapper spawned by w3wp is a high-confidence web-shell indicator.

Reporting behind it

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Malicious China Chopper Web Shell Command Pattern in IIS Worker Process (via process_creation)

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.

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