Collect OPNsense firewall logs

Supported in:

This parser extracts fields from OPNsense firewall logs (syslog and CSV formats) and maps them to the UDM. It uses grok and CSV parsing for "filterlog" application logs, handling different log formats and network protocols (TCP, UDP, ICMP, etc.) to populate UDM fields like principal, target, network, and security_result. It also adds metadata like vendor and product name, and determines the event type based on the presence of principal and target information.

Before you begin

  • Ensure that you have a Google Security Operations instance.
  • Ensure that you have privileged 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.

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.

Install BindPlane Agent

  1. For Windows installation, run the following script:
    msiexec /i "https://github.com/observIQ/bindplane-agent/releases/latest/download/observiq-otel-collector.msi" /quiet
  2. For Linux installation, run the following script:
    sudo sh -c "$(curl -fsSlL https://github.com/observiq/bindplane-agent/releases/latest/download/install_unix.sh)" install_unix.sh
  3. Additional installation options can be found in this installation guide.

Configure BindPlane Agent to ingest Syslog and send to Google SecOps

  1. Access the machine where BindPlane is installed.

  2. Edit the config.yaml file as follows:

    receivers:
  tcplog:
    # Replace the below port <54525> and IP (0.0.0.0) with your specific values
    listen_address: "0.0.0.0:54525" 

exporters:
    chronicle/chronicle_w_labels:
        compression: gzip
        # Adjust the creds location below according the placement of the credentials file you downloaded
        creds: '{ json file for creds }'
        # Replace <customer_id> below with your actual ID that you copied
        customer_id: <customer_id>
        endpoint: malachiteingestion-pa.googleapis.com
        # You can apply ingestion labels below as preferred
        ingestion_labels:
        log_type: SYSLOG
        namespace: testNamespace
        raw_log_field: body
service:
    pipelines:
        logs/source0__chronicle_w_labels-0:
            receivers:
                - tcplog
            exporters:
                - chronicle/chronicle_w_labels

  3. Restart BindPlane Agent to apply the changes using the following command: sudo systemctl bindplane restart

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, 10.10.10.10:54525).
  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.

Changes

2023-11-22

  • Newly created parser.