Collect OPNsense firewall logs

Supported in:

Google SecOps SIEM

This document explains how to ingest OPNsense firewall logs to Google Security Operations using the Bindplane agent.

OPNsense is an open-source firewall and routing platform that generates syslog messages for firewall rule matches, network connections, and system events. The parser extracts fields from CSV-formatted filterlog messages using grok and CSV parsing and maps them to the Unified Data Model (UDM).

Before you begin

Make sure you have the following prerequisites:

• A Google SecOps instance
• Windows Server 2016 or later, or Linux host with systemd
• Network connectivity between the Bindplane agent and the OPNsense firewall
• If running behind a proxy, ensure firewall ports are open per the Bindplane agent requirements
• Administrative access to the OPNsense web interface

Get Google SecOps credentials for the Bindplane agent

To authenticate the Bindplane agent to Google SecOps, choose one of the following methods:

• New deployments: Use the Chronicle API (Option 1).
• Legacy deployments: Continue using the ingestion authentication file (Option 2) until the Ingestion API is discontinued on July 20, 2027.

Option 1: Create a service account for the Chronicle API (recommended)

1. Sign in to the Google Cloud console and select the Google Cloud project that is linked to your Google SecOps instance.
2. Go to IAM & Admin > Service Accounts.
3. Click Create service account.
4. Provide the following configuration details:
   • Service account name: Enter a name for the account (for example, bindplane-ingest).
   • Service account description: Enter a description (for example, Bindplane agent log ingestion).
5. Click Create and continue.
6. In the Grant this service account access to project section, click Select a role and select Chronicle Editor.
7. Click Continue, and then click Done.
8. Click the service account you created, and then go to the Keys tab.
9. Click Add key > Create new key.
10. Select JSON and click Create. The key file is downloaded to your computer.
11. Save the key file as ingestion-auth.json in the Bindplane collector directory (/opt/observiq-otel-collector/ingestion-auth.json on Linux or C:\Program Files\observIQ OpenTelemetry Collector\ingestion-auth.json on Windows), or update creds_file_path in config.yaml to match the path where you save it.
12. Go to IAM & Admin > Settings and copy the Project number. You'll need it for the exporter configuration.

Note: The JSON key is a credential. Restrict access to the file on the Bindplane host and rotate the key according to your organization's policy.

Option 2: Download the ingestion authentication file (legacy)

1. Sign in to the Google SecOps console.
2. Go to SIEM Settings > Collection Agents.
3. Download the ingestion authentication file.
4. Save the file securely on the system where the Bindplane agent will be installed.

Note: This file authenticates the agent to the legacy Ingestion API (malachiteingestion-pa.googleapis.com), which Google has scheduled for end of life on July 20, 2027. Plan to move to Option 1 before that date.

Get Google SecOps customer ID

1. Sign in to the Google SecOps console.
2. Go to SIEM Settings > Profile.

3. Copy and save the Customer ID from the Organization Details section.

   Note: The customer ID is required for configuring the Bindplane agent exporter.

Install the Bindplane agent

Install the Bindplane agent on your Windows or Linux operating system according to the following instructions.

Windows installation

1. Open Command Prompt or PowerShell as an administrator.

2. Run the following command:

   msiexec /i "https://github.com/observIQ/bindplane-agent/releases/latest/download/observiq-otel-collector.msi" /quiet
   

3. Wait for the installation to complete.

4. Verify the installation by running:

   sc query observiq-otel-collector
   

   The service should show as RUNNING.

Linux installation

1. Open a terminal with root or sudo privileges.

2. Run the following command:

   sudo sh -c "$(curl -fsSlL https://github.com/observiq/bindplane-agent/releases/latest/download/install_unix.sh)" install_unix.sh
   

3. Wait for the installation to complete.

4. Verify the installation by running:

   sudo systemctl status observiq-otel-collector
   

   The service should show as active (running).

Additional installation resources

For additional installation options and troubleshooting, see the Bindplane agent installation guide.

Note: The Chronicle API exporter configuration requires Bindplane collector v1.106.0 or later. The previous commands install the latest release. If you're updating an existing installation, upgrade the collector before changing the configuration.

Configure the Bindplane agent to ingest syslog and send to Google SecOps

Locate the configuration file

• Linux:

  sudo nano /opt/observiq-otel-collector/config.yaml
  

• Windows:

  notepad "C:\Program Files\observIQ OpenTelemetry Collector\config.yaml"
  

Edit the configuration file

• Replace the entire contents of config.yaml with the following configuration:

  receivers:
    udplog:
      listen_address: "0.0.0.0:514"
  
  exporters:
    chronicle/opnsense:
      protocol: https
      # Region of your instance, for example us, europe, asia-southeast1
      location: <LOCATION>
      # Project number of the Google Cloud project linked to the instance
      project: '<PROJECT_NUMBER>'
      compression: gzip
      creds_file_path: '/opt/observiq-otel-collector/ingestion-auth.json'
      customer_id: '<customer_id>'
      endpoint: chronicle.googleapis.com
      log_type: OPNSENSE
      raw_log_field: body
  
  service:
    pipelines:
      logs/opnsense_to_chronicle:
        receivers:
          - udplog
        exporters:
          - chronicle/opnsense
  

Configuration parameters

Replace the following placeholders:

• Receiver configuration:

  • listen_address: IP address and port to listen on:
    • 0.0.0.0 to listen on all interfaces (recommended)
    • Port 514 is the standard syslog port (requires root on Linux; use 1514 for non-root)

• Exporter configuration:

  • creds_file_path: Full path to the service account JSON key file (Option 1):
    • Linux: /opt/observiq-otel-collector/ingestion-auth.json
    • Windows: C:\Program Files\observIQ OpenTelemetry Collector\ingestion-auth.json
  • customer_id: Customer ID copied from the Google SecOps console
  • location: Replace <LOCATION> with the region of your Google SecOps instance (for example, us, europe, or asia-southeast1). The exporter prefixes chronicle.googleapis.com with this value. See Regional Endpoints for the complete list.
  • project: Replace <PROJECT_NUMBER> with the project number from IAM & Admin > Settings.
  • endpoint: Keep set to chronicle.googleapis.com.

Legacy ingestion API exporter

• If you use the ingestion authentication file from Option 2, replace the exporters block with the following. Set creds_file_path to the path to the ingestion authentication file, and if your instance is outside the US, replace malachiteingestion-pa.googleapis.com with your regional endpoint (for example, europe-malachiteingestion-pa.googleapis.com).

  exporters:
    chronicle/opnsense:
      compression: gzip
      creds_file_path: '/opt/observiq-otel-collector/ingestion-auth.json'
      customer_id: '<customer_id>'
      endpoint: malachiteingestion-pa.googleapis.com
      log_type: OPNSENSE
      raw_log_field: body
  

Note: This exporter will stop working when the Ingestion API is discontinued on July 20, 2027.

Save the configuration file

• After editing, save the file:
  • Linux: Press Ctrl+O, then Enter, then Ctrl+X
  • Windows: Click File > Save

Restart the Bindplane agent to apply the changes

• To restart the Bindplane agent in Linux, run the following command:

  sudo systemctl restart observiq-otel-collector
  

  1. Verify the service is running:

     sudo systemctl status observiq-otel-collector
     

  2. Check logs for errors:

     sudo journalctl -u observiq-otel-collector -f
     

• To restart the Bindplane agent in Windows, choose one of the following options:

  • Command Prompt or PowerShell as administrator:

    net stop observiq-otel-collector && net start observiq-otel-collector
    

  • Services console:

    1. Press Win+R, type services.msc, and press Enter.
    2. Locate observIQ OpenTelemetry Collector.
    3. Right-click and select Restart.

    4. Verify the service is running:

       sc query observiq-otel-collector
       

    5. Check logs for errors:

       type "C:\Program Files\observIQ OpenTelemetry Collector\log\collector.log"
       

Add syslog server configuration to OPNsense

1. Sign in to the OPNsense web interface.
2. Go to System > Settings > Logging.
3. In the Remote Logging section, enable Send logs to remote syslog server by checking the box.
4. In the Remote Syslog Servers field, enter the IP address of the syslog server, including the port (for example, 10.10.10.10:514).
5. Select Local0 as the syslog facility.
6. Set syslog level as Alert.
7. Click Save to apply the changes.

UDM mapping table

Log Field	UDM Mapping	Logic
column1	security_result.rule_id	Directly mapped from column1.
column10	additional.fields[].key: "tos" additional.fields[].value.string_value: Value of column10	Directly mapped from column10, nested under additional.fields with key "tos".
column12	additional.fields[].key: "ttl" additional.fields[].value.string_value: Value of column12	Directly mapped from column12, nested under additional.fields with key "ttl".
column13	additional.fields[].key: "Id" additional.fields[].value.string_value: Value of column13	Directly mapped from column13, nested under additional.fields with key "Id".
column14	additional.fields[].key: "offset" additional.fields[].value.string_value: Value of column14	Directly mapped from column14, nested under additional.fields with key "offset".
column15	additional.fields[].key: "flags" additional.fields[].value.string_value: Value of column15	Directly mapped from column15, nested under additional.fields with key "flags".
column17	network.ip_protocol	Directly mapped from column17 after converting to uppercase.
column18	network.received_bytes	Directly mapped from column18 after converting to unsigned integer.
column19	principal.ip	Directly mapped from column19.
column20	target.ip	Directly mapped from column20.
column21	principal.port (if column17 is TCP or UDP) additional.fields[].key: "data_length" additional.fields[].value.string_value: Extracted value (if column17 is ICMP, GRE, ESP, or IGMP)	If column17 is TCP/UDP, directly mapped from column21 and converted to integer. Otherwise, the "datalength" value is extracted using grok and placed in additional.fields with key "data_length".
column22	target.port	Directly mapped from column22 if column17 is TCP or UDP, and converted to integer.
column24	additional.fields[].key: "tcp_flags" additional.fields[].value.string_value: Value of column24	Directly mapped from column24 if column17 is TCP, nested under additional.fields with key "tcp_flags".
column29	additional.fields[].key: "tcp_options" additional.fields[].value.string_value: Value of column29	Directly mapped from column29 if column17 is TCP, nested under additional.fields with key "tcp_options".
column4	additional.fields[].key: "tracker" additional.fields[].value.string_value: Value of column4	Directly mapped from column4, nested under additional.fields with key "tracker".
column5	additional.fields[].key: "interface" additional.fields[].value.string_value: Value of column5	Directly mapped from column5, nested under additional.fields with key "interface".
column6	security_result.rule_type	Directly mapped from column6.
column7	security_result.action	Mapped from column7. If "block", converted to uppercase "BLOCK". If "pass", set to "ALLOW".
column8	network.direction	Mapped from column8. If "in", set to "INBOUND". If "out", set to "OUTBOUND".
domain	principal.administrative_domain	Directly mapped from the grok-extracted domain. Set to "NETWORK_CONNECTION" if both principal and target IP addresses are present, otherwise "GENERIC_EVENT". Hardcoded to "OPNSENSE". Hardcoded to "OPNSENSE".
message	Various fields	Parsed using grok and csv filters to extract various fields. See other rows for specific mappings.
ts	metadata.event_timestamp.seconds, timestamp.seconds	Parsed from the message field using grok and then converted to a timestamp. The seconds value is used to populate both metadata.event_timestamp.seconds and timestamp.seconds.
application	principal.application	Directly mapped from the grok-extracted application.
column27	event.idm.read_only_udm.additional.fields	Mapped from changelog
column2	event.idm.read_only_udm.additional.fields	Mapped from changelog
column3	event.idm.read_only_udm.additional.fields	Mapped from changelog
column11	event.idm.read_only_udm.additional.fields	Mapped from changelog
column26	event.idm.read_only_udm.additional.fields	Mapped from changelog
column28	event.idm.read_only_udm.additional.fields	Mapped from changelog
column25	event.idm.read_only_udm.additional.fields	Mapped from changelog
column16	event.idm.read_only_udm.additional.fields	Mapped from changelog
column9	event.idm.read_only_udm.additional.fields	Mapped from changelog

Change Log

View the Change Log for this parser

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