Detection rules › Sigma
Chopper Webshell Process Pattern
Detects patterns found in process executions cause by China Chopper like tiny (ASPX) webshells
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | |
| Discovery |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 1: Process creation |
| Security-Auditing | Event ID 4688: A new process has been created. |
Rule body
title: Chopper Webshell Process Pattern
id: fa3c117a-bc0d-416e-a31b-0c0e80653efb
status: test
description: Detects patterns found in process executions cause by China Chopper like tiny (ASPX) webshells
references:
- https://www.microsoft.com/security/blog/2022/09/30/analyzing-attacks-using-the-exchange-vulnerabilities-cve-2022-41040-and-cve-2022-41082/
author: Florian Roth (Nextron Systems), MSTI (query)
date: 2022-10-01
tags:
- attack.persistence
- attack.discovery
- attack.t1505.003
- attack.t1018
- attack.t1033
- attack.t1087
logsource:
category: process_creation
product: windows
detection:
selection_origin:
- Image|endswith: '\w3wp.exe'
- ParentImage|endswith: '\w3wp.exe'
selection_cmdline:
CommandLine|contains:
- '&ipconfig&echo'
- '&quser&echo'
- '&whoami&echo'
- '&c:&echo'
- '&cd&echo'
- '&dir&echo'
- '&echo [E]'
- '&echo [S]'
condition: all of selection_*
falsepositives:
- Unknown
level: high
Stages and Predicates
Stage 0: condition
all of selection_*Stage 1: selection_origin
selection_origin:
- Image|endswith: '\w3wp.exe'
- ParentImage|endswith: '\w3wp.exe'
Stage 2: selection_cmdline
selection_cmdline:
CommandLine|contains:
- '&ipconfig&echo'
- '&quser&echo'
- '&whoami&echo'
- '&c:&echo'
- '&cd&echo'
- '&dir&echo'
- '&echo [E]'
- '&echo [S]'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
CommandLine | match |
| field:"CommandLine" kind:match |
Image | ends_with |
| field:"Image" kind:ends_with value:"\w3wp.exe" |
ParentImage | ends_with |
| field:"ParentImage" kind:ends_with value:"\w3wp.exe" |