Collect Active Countermeasures AC-Hunter logs

Parser Version: 3.0

Supported in:

Google SecOps SIEM

This document explains how to ingest Active Countermeasures AC-Hunter logs to Google Security Operations using Bindplane.

AC-Hunter is a network threat detection platform by Active Countermeasures that performs automated threat hunting by analyzing network traffic to identify compromised systems communicating with command and control servers. AC-Hunter runs in Docker containers on a Linux server and can forward threat alerts via the syslog protocol to a SIEM or centralized logging server.

Before you begin

Make sure you have the following prerequisites:

• A Google SecOps instance.
• Windows Server 2016 or later, or a Linux host with systemd.
• If running behind a proxy, ensure firewall ports are open per the Bindplane agent requirements.
• Privileged access (SSH with sudo) to the Active Countermeasures AC-Hunter server to edit the configuration file.
• AC-Hunter version 5.3.0 or later (earlier versions contain a bug that blocks sending syslog messages).
• Network path from the AC-Hunter server to the Bindplane agent host on your chosen syslog port (UDP or TCP).
• IP forwarding enabled on the AC-Hunter host to allow Docker containers to send syslog to external servers.

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.

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
   

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
   

Additional installation resources

For additional installation options, see 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/ac_hunter:
      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: AI_HUNTER
      raw_log_field: body
  
  service:
    pipelines:
      logs/ac_hunter_to_chronicle:
        receivers:
          - udplog
        exporters:
          - chronicle/ac_hunter
  

Configuration parameters

Replace the following placeholders:

• Receiver configuration:

  • udplog: Use udplog for UDP syslog or tcplog for TCP syslog. Match the protocol configured in AC-Hunter.
  • 0.0.0.0:514: IP address and port to listen on. Use 0.0.0.0 to listen on all interfaces.

• Exporter configuration:

  • <CUSTOMER_ID>: Google SecOps Customer ID copied in the previous step.
  • /opt/observiq-otel-collector/ingestion-auth.json: 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
  • 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/ac_hunter:
      compression: gzip
      creds_file_path: '/opt/observiq-otel-collector/ingestion-auth.json'
      customer_id: '<CUSTOMER_ID>'
      endpoint: malachiteingestion-pa.googleapis.com
      log_type: AI_HUNTER
      raw_log_field: body
  

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

Restart the Bindplane agent to apply the changes

To restart the Bindplane agent in Linux:

1. Run the following command:

   sudo systemctl restart observiq-otel-collector
   

2. Verify the service is running:

   sudo systemctl status observiq-otel-collector
   

3. Check logs for errors:

   sudo journalctl -u observiq-otel-collector -f
   

To restart the Bindplane agent in Windows:

1. 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.

2. Verify the service is running:

   sc query observiq-otel-collector
   

3. Check logs for errors:

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

Configure syslog forwarding on Active Countermeasures AC-Hunter

1. Sign in to the AC-Hunter server via SSH with privileged access.

2. Back up the existing configuration file:

   sudo cp /etc/AI-Hunter/config.yaml /etc/AI-Hunter/config.yaml.backup
   

3. Open the configuration file in a text editor:

   sudo nano /etc/AI-Hunter/config.yaml
   

4. Locate the Alert: section and the nested Syslog: section. Provide the following configuration details:

   Alert:
       Syslog:
           Threshold: 20
           Protocol: "udp"
           Address: "BINDPLANE_IP:514"
           Tag: " AC-Hunter "
   

   • Threshold: Enter the minimum threat score to trigger alerts (for example, 20). Systems with scores at or above this value generate syslog alerts.
   • Protocol: Select "udp" or "tcp" to match the Bindplane agent receiver configuration. Use "" (empty string) to write to the host /dev/log for rsyslog forwarding.
   • Address: Enter the Bindplane agent IP address and port (for example, "10.1.2.3:514").
   • Tag: Enter an optional tag for log identification (for example, " AC-Hunter "). Include a trailing space before the closing quote so the tag does not run into the message text.
   Note: Indentation is critical in this YAML file. Singly indented lines use 4 spaces, doubly indented lines use 8 spaces. Do not use tabs. Validate the file at yamllint.com before saving.

5. Save the configuration file and exit the editor.

6. Restart AC-Hunter to apply the changes:

   hunt up -d --force-recreate
   

7. Wait until approximately 20 minutes past the next hour. AC-Hunter imports new hourly logs from sensors and sends syslog alerts for systems that exceed the configured threshold during this import cycle.

8. Verify that syslog messages are arriving at the Bindplane agent host by checking the local syslog log file:

   sudo tail -f /var/log/syslog
   

   Note: AC-Hunter syslog messages use the user.alert facility and follow this format: <timestamp> <hostname> AI-Hunter[<pid>]: Host: <IP> Score: <score> PreviousScore: <prev_score> Database: <db_name>

UDM mapping table

Log Field	UDM Mapping	Logic
api_msg_label	additional.fields	Merged
prev_score	metadata.description	Directly mapped
score	metadata.description	Directly mapped
ts_date	metadata.event_timestamp	Parsed as MMM dd HH:mm:ss
ts_iso8601	metadata.event_timestamp	Parsed as ISO8601
has_principal	metadata.event_type	Mapped: true → STATUS_UNCATEGORIZED
src_ip	principal.asset.ip	Merged
src_ip	principal.ip	Merged
blacklist_avg_bytes_label	principal.labels	Merged
blacklist_in_label	principal.labels	Merged
blacklist_out_label	principal.labels	Merged
database_label	principal.labels	Merged
dns_txt_query_label	principal.labels	Merged
invalid_cert_label	principal.labels	Merged
max_beacon_label	principal.labels	Merged
max_duration_label	principal.labels	Merged
prev_score_label	principal.labels	Merged
rare_client_label	principal.labels	Merged
score_label	principal.labels	Merged
unexpected_proto_label	principal.labels	Merged
source_module_label	principal.resource.attribute.labels	Merged
domain	target.asset.hostname	Directly mapped
domain	target.hostname	Directly mapped
N/A	metadata.event_type	Constant: STATUS_UNCATEGORIZED
N/A	metadata.product_name	Constant: AI hunter
N/A	metadata.vendor_name	Constant: Active Countermeasures

Change Log

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