Winlogbeat not dropping multicast traffic using drop_event.when.or

Elastic Stack Beats
1

Using drop_event.when.or I've attempted to exclude multicast traffic logs from being sent over as well as logs containing the keyword "zabbix". However, I am still receiving these events.

winlogbeat.event_logs:
  - name: Application
    ignore_older: 72h

  - name: System
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - drop_event.when.or:
        - contains.event_data: "224.0.0" #Drop multicast traffic
        - contains.event_data: "239.255.255.250" #Drop multicast traffic
        - contains.event_data: "zabbix" #Drop zabbix traffic

  - name: Security
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - drop_event.when.or:
        - contains.event_data: "224.0.0" #Drop multicast traffic
        - contains.event_data: "239.255.255.250" #Drop multicast traffic
        - contains.event_data: "zabbix" #Drop zabbix traffic
      - script:
          lang: javascript
          id: security
          file: ${path.home}/module/security/config/winlogbeat-security.js

  - name: Microsoft-Windows-Sysmon/Operational
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - script:
          lang: javascript
          id: sysmon
          file: ${path.home}/module/sysmon/config/winlogbeat-sysmon.js

  - name: Windows PowerShell
    event_id: 400, 403, 600, 800
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - script:
          lang: javascript
          id: powershell
          file: ${path.home}/module/powershell/config/winlogbeat-powershell.js

  - name: Microsoft-Windows-PowerShell/Operational
    event_id: 4103, 4104, 4105, 4106
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - script:
          lang: javascript
          id: powershell
          file: ${path.home}/module/powershell/config/winlogbeat-powershell.js

  - name: ForwardedEvents
    tags: [forwarded]
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - script:
          when.equals.winlog.channel: Security
          lang: javascript
          id: security
          file: ${path.home}/module/security/config/winlogbeat-security.js
      - script:
          when.equals.winlog.channel: Microsoft-Windows-Sysmon/Operational
          lang: javascript
          id: sysmon
          file: ${path.home}/module/sysmon/config/winlogbeat-sysmon.js
      - script:
          when.equals.winlog.channel: Windows PowerShell
          lang: javascript
          id: powershell
          file: ${path.home}/module/powershell/config/winlogbeat-powershell.js
      - script:
          when.equals.winlog.channel: Microsoft-Windows-PowerShell/Operational
          lang: javascript
          id: powershell
          file: ${path.home}/module/powershell/config/winlogbeat-powershell.js
2

I changed the field to winlog.event_data for the security log just to test and still no luck:

winlogbeat.event_logs:
  - name: Application
    ignore_older: 72h

  - name: System
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - drop_event.when.or:
        - contains.winlog.event_data: "224.0.0" #Drop multicast traffic
        - contains.winlog.event_data: "239.255.255.250" #Drop multicast traffic
        - contains.winlog.event_data: "zabbix" #Drop zabbix traffic

  - name: Security
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - drop_event.when.or:
        - contains.winlog.event_data: "224.0.0" #Drop multicast traffic
        - contains.winlog.event_data: "239.255.255.250" #Drop multicast traffic
        - contains.winlog.event_data: "zabbix" #Drop zabbix traffic
      - script:
          lang: javascript
          id: security
          file: ${path.home}/module/security/config/winlogbeat-security.js

  - name: Microsoft-Windows-Sysmon/Operational
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - drop_event.when.or:
        - contains.event_data: "224.0.0" #Drop multicast traffic
        - contains.event_data: "239.255.255.250" #Drop multicast traffic
        - contains.event_data: "zabbix" #Drop zabbix traffic
      - script:
          lang: javascript
          id: sysmon
          file: ${path.home}/module/sysmon/config/winlogbeat-sysmon.js

  - name: Windows PowerShell
    event_id: 400, 403, 600, 800
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - script:
          lang: javascript
          id: powershell
          file: ${path.home}/module/powershell/config/winlogbeat-powershell.js

  - name: Microsoft-Windows-PowerShell/Operational
    event_id: 4103, 4104, 4105, 4106
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - script:
          lang: javascript
          id: powershell
          file: ${path.home}/module/powershell/config/winlogbeat-powershell.js

  - name: ForwardedEvents
    tags: [forwarded]
    processors:
      - drop_fields:
          fields: [winlog.provider_guid, winlog.process.pid, winlog.process.thread.id, winlog.version, winlog.event_data.ErrorSourceTable]
      - script:
          when.equals.winlog.channel: Security
          lang: javascript
          id: security
          file: ${path.home}/module/security/config/winlogbeat-security.js
      - script:
          when.equals.winlog.channel: Microsoft-Windows-Sysmon/Operational
          lang: javascript
          id: sysmon
          file: ${path.home}/module/sysmon/config/winlogbeat-sysmon.js
      - script:
          when.equals.winlog.channel: Windows PowerShell
          lang: javascript
          id: powershell
          file: ${path.home}/module/powershell/config/winlogbeat-powershell.js
      - script:
          when.equals.winlog.channel: Microsoft-Windows-PowerShell/Operational
          lang: javascript
          id: powershell
          file: ${path.home}/module/powershell/config/winlogbeat-powershell.js
3

This won't match because contains acts like a substring match and event_data is an object. If you can change event_data to a leaf field that contains a string like winlog.event_data.IpAddress things will work better.

4

And BTW there is a condition for matching network addresses. See https://www.elastic.co/guide/en/beats/winlogbeat/7.7/defining-processors.html#condition-network.

- drop_event:
    when.network:
      winlog.event_data.IpAddress: [multicast]
5

Thanks for your reply Andrew. I thought about it some last night and came to that conclusion so I modified the line to:

processors:
      - drop_event.when.or:
          - equals.event_data.ProcessName: "zabbix_agentd.exe"

This was after looking in Kibana to find ProcessName:

Dec 22, 2020 @ 22:55:43.566

process_name:
    zabbix_agentd.exe
opcode:
    Info
level:
    information
src_ip_rfc:
    RFC_1918
 .......

Unfortunately this did not work either. I tried modifying it to equals.winlog.event_data.ProcessName with no luck.

6

I also tried this one and had no luck with filtering out multicast:

    #-------------------------- Windows Logs To Collect -----------------------------
    winlogbeat.event_logs:
      - name: Application
        ignore_older: 30m
      - name: Security
        ignore_older: 30m
        processors:
          - drop_event:
              when.network:
                winlog.event_data.IpAddress: [multicast]
      - name: System
        ignore_older: 30m
      - name: Microsoft-windows-sysmon/operational
        ignore_older: 30m
      - name: Microsoft-windows-PowerShell/Operational
        ignore_older: 30m
        event_id: 4103, 4104
      - name: Windows PowerShell
        event_id: 400,600
        ignore_older: 30m
      - name: Microsoft-Windows-WMI-Activity/Operational
        event_id: 5857,5858,5859,5860,5861

This was received a few minutes after making the change and restarting the winlogbeat service.

    event_original_message	
    The Windows Filtering Platform has permitted a connection.

    Application Information:
    	Process ID:		884
    	Application Name:	\device\harddiskvolume2\windows\system32\svchost.exe

    Network Information:
    	Direction:		Inbound
    	Source Address:		224.0.0.252
    	Source Port:		5355
    	Destination Address:	10.0.0.188
    	Destination Port:		62098
    	Protocol:		17

    Filter Information:
    	Filter Run-Time ID:	0
    	Layer Name:		Receive/Accept
    	Layer Run-Time ID:	44
    event_original_time	
    2020-12-23T17:21:30.156Z
    keywords	Audit Success
    level	information
    log_name	Security
7

This worked. Guess I have to do another one for DestinationAddress? Still unable to filter the zabbix events unfortunately. Tried filtering it based on source port and it did not work.

processors:
  - drop_event.when.or:
      - network:
          winlog.event_data.SourceAddress: [multicast]
8

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