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 ingestion authentication file

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

3. Download the Ingestion Authentication File. Save the file securely on the system where Bindplane will be installed.

   Note: This JSON file contains credentials for authenticating the Bindplane agent to Google SecOps.

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.

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:
          compression: gzip
          creds_file_path: '/etc/bindplane-agent/ingestion-auth.json'
          customer_id: '<customer_id>'
          endpoint: malachiteingestion-pa.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 ingestion authentication file:
    • Linux: /etc/bindplane-agent/ingestion-auth.json
    • Windows: C:\Program Files\observIQ OpenTelemetry Collector\ingestion-auth.json
  • customer_id: Customer ID copied from the Google SecOps console
  • endpoint: Regional endpoint URL:
    • US: malachiteingestion-pa.googleapis.com
    • Europe: europe-malachiteingestion-pa.googleapis.com
    • Asia: asia-southeast1-malachiteingestion-pa.googleapis.com
    • See Regional Endpoints for complete list

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.

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