Webshell Detection With Command Line Keywords — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems), Jonhnathan Ribeiro, Anton Kutepov, oscd.community, Chad Hudson, Matt Anderson. Source status: test; severity: high. Source dates: 2017-01-01 / 2024-12-14.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 2db3e9674944cc3fe111ab792052016075465190d72c55eabf0e5670b9cae1a4

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Webshell Detection With Command Line Keywords
id: bed2a484-9348-4143-8a8a-b801c979301c
status: test
description: Detects certain command line parameters often used during reconnaissance activity via web shells
references:
    - https://www.fireeye.com/blog/threat-research/2013/08/breaking-down-the-china-chopper-web-shell-part-ii.html
    - https://unit42.paloaltonetworks.com/bumblebee-webshell-xhunt-campaign/
    - https://www.huntress.com/blog/threat-advisory-oh-no-cleo-cleo-software-actively-being-exploited-in-the-wild
author: Florian Roth (Nextron Systems), Jonhnathan Ribeiro, Anton Kutepov, oscd.community, Chad Hudson, Matt Anderson
date: 2017-01-01
modified: 2024-12-14
tags:
    - attack.persistence
    - attack.discovery
    - attack.t1505.003
    - attack.t1018
    - attack.t1033
    - attack.t1087
logsource:
    category: process_creation
    product: windows
detection:
    selection_webserver_image:
        ParentImage|endswith:
            - '\w3wp.exe'
            - '\php-cgi.exe'
            - '\nginx.exe'
            - '\httpd.exe'
            - '\caddy.exe'
            - '\ws_tomcatservice.exe'
    selection_webserver_characteristics_tomcat1:
        ParentImage|endswith:
            - '\java.exe'
            - '\javaw.exe'
        ParentImage|contains:
            - '-tomcat-'
            - '\tomcat'
    selection_webserver_characteristics_tomcat2:
        ParentImage|endswith:
            - '\java.exe'
            - '\javaw.exe'
        CommandLine|contains:
            - 'catalina.jar'
            - 'CATALINA_HOME'
    selection_susp_net_utility:
        OriginalFileName:
            - 'net.exe'
            - 'net1.exe'
        CommandLine|contains:
            - ' user '
            - ' use '
            - ' group '
    selection_susp_ping_utility:
        OriginalFileName: 'ping.exe'
        CommandLine|contains: ' -n '
    selection_susp_change_dir:
        CommandLine|contains:
            - '&cd&echo'  # china chopper web shell
            - 'cd /d '  # https://www.computerhope.com/cdhlp.htm
    selection_susp_wmic_utility:
        OriginalFileName: 'wmic.exe'
        CommandLine|contains: ' /node:'
    selection_susp_powershell_cli:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
        CommandLine|contains:
            - ' -enc '
            - ' -EncodedCommand '
            - ' -w hidden '
            - ' -windowstyle hidden'
            - '.WebClient).Download'
    selection_susp_misc_discovery_binaries:
        - Image|endswith:
              - '\dsquery.exe'
              - '\find.exe'
              - '\findstr.exe'
              - '\ipconfig.exe'
              - '\netstat.exe'
              - '\nslookup.exe'
              - '\pathping.exe'
              - '\quser.exe'
              - '\schtasks.exe'
              - '\systeminfo.exe'
              - '\tasklist.exe'
              - '\tracert.exe'
              - '\ver.exe'
              - '\wevtutil.exe'
              - '\whoami.exe'
        - OriginalFileName:
              - 'dsquery.exe'
              - 'find.exe'
              - 'findstr.exe'
              - 'ipconfig.exe'
              - 'netstat.exe'
              - 'nslookup.exe'
              - 'pathping.exe'
              - 'quser.exe'
              - 'schtasks.exe'
              - 'sysinfo.exe'
              - 'tasklist.exe'
              - 'tracert.exe'
              - 'ver.exe'
              - 'VSSADMIN.EXE'
              - 'wevtutil.exe'
              - 'whoami.exe'
    selection_susp_misc_discovery_commands:
        CommandLine|contains:
            - ' Test-NetConnection '
            - 'dir \'  # remote dir: dir \<redacted IP #3>\C$:\windows\temp\*.exe
    condition: 1 of selection_webserver_* and 1 of selection_susp_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.fireeye.com/blog/threat-research/2013/08/breaking-down-the-china-chopper-web-shell-part-ii.html
• https://unit42.paloaltonetworks.com/bumblebee-webshell-xhunt-campaign/
• https://www.huntress.com/blog/threat-advisory-oh-no-cleo-cleo-software-actively-being-exploited-in-the-wild