Collect Cloud NAT logs

Supported in:

This document describes how you can collect Cloud NAT logs by enabling Google Cloud telemetry ingestion to Google Security Operations and how log fields of Cloud NAT logs map into Google Security Operations Unified Data Model (UDM) fields.

For more information, see Data ingestion to Google Security Operations.

A typical deployment consists of Cloud NAT logs enabled for ingestion to Google Security Operations. Each customer deployment might differ from this representation and might be more complex.

The deployment contains the following components:

  • Google Cloud: The Google Cloud services and products from which you collect logs.

  • Cloud NAT logs: The Cloud NAT logs that are enabled for ingestion into Google Security Operations.

  • Google Security Operations: Google Security Operations retains and analyzes the logs from Cloud NAT.

An ingestion label identifies the parser which normalizes raw log data to structured UDM format. The information into this document applies to the parser with the GCP_CLOUD_NAT ingestion label.

Before you begin

  • Ensure that all systems in the deployment architecture are configured in the UTC time zone.

Configure Google Cloud to ingest Cloud NAT logs

For more information on how to ingest logs to Google Security Operations, see Ingest Google Cloud logs to Google Security Operations.

If you encounter issues when you ingest Cloud NAT logs, contact Google Security Operations support.

Field mapping reference

This section explains how the Google Security Operations parser maps Cloud NAT fields to Google Security Operations Unified Data Model (UDM) fields.

Log field UDM mapping Logic
metadata.event_type The metadata.event_type UDM field is set to NETWORK_CONNECTION.
metadata.product_name The metadata.product_name UDM field is set to GCP Cloud NAT.
metadata.vendor_name The metadata.vendor_name UDM field is set to Google Cloud Platform.
receiveTimestamp metadata.collected_timestamp
timestamp metadata.event_timestamp
logName security_result.category_details
insertId metadata.product_log_id
network.direction The network.direction UDM field is set to OUTBOUND.
network.ip_protocol If the jsonPayload.connection.protocol log field value contains one of the following values, then the network.ip_protocol UDM field is set to ICMP.
  • 1
  • ICMP
  • ICMPV6
  • 58
  • 1.0
  • 58.0
Else, if the jsonPayload.connection.protocol log field value contains one of the following values, then the network.ip_protocol UDM field is set to IGMP.
  • 2
  • IGMP
  • 2.0
Else, if the jsonPayload.connection.protocol log field value contains one of the following values, then the network.ip_protocol UDM field is set to TCP.
  • 6
  • TCP
  • 6.0
Else, if the jsonPayload.connection.protocol log field value contains one of the following values, then the network.ip_protocol UDM field is set to UDP.
  • 17
  • UDP
  • 17.0
Else, if the jsonPayload.connection.protocol log field value contains one of the following values, then the network.ip_protocol UDM field is set to IP6IN4.
  • 41
  • IP6IN4
  • 41.0
Else, if the jsonPayload.connection.protocol log field value contains one of the following values, then the network.ip_protocol UDM field is set to GRE.
  • 47
  • GRE
  • 47.0
Else, if the jsonPayload.connection.protocol log field value contains one of the following values, then the network.ip_protocol UDM field is set to ESP.
  • 50
  • ESP
  • 50.0
Else, if the jsonPayload.connection.protocol log field value contains one of the following values, then the network.ip_protocol UDM field is set to EIGRP.
  • 88
  • EIGRP
  • 88.0
Else, if the jsonPayload.connection.protocol log field value contains one of the following values, then the network.ip_protocol UDM field is set to ETHERIP.
  • 97
  • ETHERIP
  • 97.0
Else, if the jsonPayload.connection.protocol log field value contains one of the following values, then the network.ip_protocol UDM field is set to PIM.
  • 103
  • PIM
  • 103.0
Else, if the jsonPayload.connection.protocol log field value contains one of the following values, then the network.ip_protocol UDM field is set to VRRP.
  • 112
  • VRRP
  • 112.0
jsonPayload.connection.src_ip principal.ip
jsonPayload.connection.src_port principal.port
jsonPayload.connection.nat_ip principal.nat_ip
jsonPayload.connection.nat_port principal.nat_port
jsonPayload.vpc.project_id intermediary.resource_ancestors.name If the jsonPayload.vpc.project_id log field value is not empty, then the //cloudresourcemanager.googleapis.com/projects/%{jsonPayload.vpc.project_id} log field is mapped to the intermediary.resource_ancestors.name UDM field.
intermediary.resource_ancestors.resource_type If the jsonPayload.vpc.project_id log field value is not empty, then the intermediary.resource_ancestors.resource_type UDM field is set to CLOUD_PROJECT.
intermediary.resource_ancestors.attribute.cloud.environment If the jsonPayload.vpc.project_id log field value is not empty, then the intermediary.resource_ancestors.attribute.cloud.environment UDM field is set to GOOGLE_CLOUD_PLATFORM.
jsonPayload.vpc.vpc_name intermediary.resource_ancestors.name
intermediary.resource_ancestors.resource_type If the jsonPayload.vpc.vpc_name log field value is not empty or the jsonPayload.vpc.subnetwork_name log field value is not empty, then the intermediary.resource_ancestors.resource_type UDM field is set to VPC_NETWORK.
intermediary.resource_ancestors.attribute.cloud.environment If the jsonPayload.vpc.vpc_name log field value is not empty or the jsonPayload.vpc.subnetwork_name log field value is not empty, then the intermediary.resource_ancestors.attribute.cloud.environment UDM field is set to GOOGLE_CLOUD_PLATFORM.
jsonPayload.vpc.subnetwork_name intermediary.resource_ancestors.attribute.labels [vpc_subnetwork_name]
jsonPayload.gateway_identifiers.gateway_name intermediary.resource.name
intermediary.resource.resource_type If the jsonPayload.gateway_identifiers.gateway_name log field value is not empty or the resource.type log field value is not empty or the resource.labels.region log field value is not empty or the jsonPayload.gateway_identifiers.router_name log field value is not empty or the resource.labels.router_id log field value is not empty, then the intermediary.resource.resource_type UDM field is set to BACKEND_SERVICE.
resource.type intermediary.resource.resource_subtype
jsonPayload.gateway_identifiers.region intermediary.location.name
intermediary.resource.attribute.cloud.environment If the jsonPayload.gateway_identifiers.gateway_name log field value is not empty or the resource.type log field value is not empty or the resource.labels.region log field value is not empty or the jsonPayload.gateway_identifiers.router_name log field value is not empty or the resource.labels.router_id log field value is not empty, then the intermediary.resource.attribute.cloud.environment UDM field is set to GOOGLE_CLOUD_PLATFORM.
resource.labels.region intermediary.resource.attribute.cloud.availability_zone
jsonPayload.gateway_identifiers.router_name intermediary.resource.attribute.labels [gateway_identifiers_router_name]
resource.labels.router_id intermediary.resource.attribute.labels [resource_labels_router_id]
jsonPayload.endpoint.project_id principal.resource_ancestors.name If the jsonPayload.endpoint.project_id log field value is not empty, then the //cloudresourcemanager.googleapis.com/projects/%{jsonPayload.endpoint.project_id} log field is mapped to the principal.resource_ancestors.name UDM field.
principal.resource_ancestors.resource_type If the jsonPayload.endpoint.project_id log field value is not empty, then the principal.resource_ancestors.resource_type UDM field is set to CLOUD_PROJECT.
principal.resource_ancestors.attribute.cloud.environment If the jsonPayload.endpoint.project_id log field value is not empty, then the principal.resource_ancestors.attribute.cloud.environment UDM field is set to GOOGLE_CLOUD_PLATFORM.
jsonPayload.endpoint.vm_name principal.hostname
jsonPayload.endpoint.vm_name principal.asset.hostname
jsonPayload.endpoint.vm_name principal.resource.name
principal.resource.resource_type If the jsonPayload.endpoint.vm_name log field value is not empty or the jsonPayload.endpoint.zone log field value is not empty, then the principal.resource.resource_type UDM field is set to VIRTUAL_MACHINE.
principal.resource.attribute.cloud.environment If the jsonPayload.endpoint.vm_name log field value is not empty or the jsonPayload.endpoint.zone log field value is not empty, then the principal.resource.attribute.cloud.environment UDM field is set to GOOGLE_CLOUD_PLATFORM.
jsonPayload.endpoint.zone principal.resource.attribute.cloud.availability_zone
jsonPayload.endpoint.region principal.location.name
jsonPayload.connection.dest_ip target.ip
jsonPayload.connection.dest_port target.port
jsonPayload.destination.geo_location.city target.location.city
jsonPayload.destination.geo_location.country target.location.country_or_region
jsonPayload.destination.geo_location.region target.location.name
jsonPayload.destination.geo_location.continent target.labels [destination_geo_location_continent] (deprecated)
jsonPayload.destination.geo_location.continent additional.fields [destination_geo_location_continent]
jsonPayload.destination.geo_location.asn network.asn
jsonPayload.destination.instance.project_id target.resource_ancestors.name If the jsonPayload.destination.instance.project_id log field value is not empty, then the //cloudresourcemanager.googleapis.com/projects/%{jsonPayload.destination.instance.project_id} log field is mapped to the target.resource_ancestors.name UDM field.
target.resource_ancestors.resource_type If the jsonPayload.destination.instance.project_id log field value is not empty, then the target.resource_ancestors.resource_type UDM field is set to CLOUD_PROJECT.
target.resource_ancestors.attribute.cloud.environment If the jsonPayload.destination.instance.project_id log field value is not empty, then the target.resource_ancestors.attribute.cloud.environment UDM field is set to GOOGLE_CLOUD_PLATFORM.
jsonPayload.destination.instance.vm_name target.hostname
jsonPayload.destination.instance.vm_name target.asset.hostname
jsonPayload.destination.instance.vm_name target.resource.name
target.resource.resource_type If the jsonPayload.destination.instance.vm_name log field value is not empty, then the target.resource_ancestors.resource_type UDM field is set to VIRTUAL_MACHINE.
target.resource.attribute.cloud.environment If the jsonPayload.destination.instance.vm_name log field value is not empty, then the target.resource.attribute.cloud.environment UDM field is set to GOOGLE_CLOUD_PLATFORM.
jsonPayload.destination.instance.zone target.resource.attribute.cloud.availability_zone
jsonPayload.destination.instance.region target.location.name If the jsonPayload.destination.geo_location.region log field value is empty, then the jsonPayload.destination.instance.region log field is mapped to the target.location.name UDM field.
security_result.action If the jsonPayload.allocation_status log field value is equal to OK, then the security_result.action UDM field is set to ALLOW.

Else, if the jsonPayload.allocation_status log field value is equal to DROPPED, then the security_result.action UDM field is set to BLOCK.
jsonPayload.allocation_status security_result.action_details
labels about.resource.attribute.labels
resource.labels.project_id about.resource.attribute.labels [resource_project_id] If the resource.labels.project_id log field value is not empty, then the //cloudresourcemanager.googleapis.com/projects/%{resource.labels.project_id} log field is mapped to the about.resource.attribute.labels.resource_project_id UDM field.
resource.labels.gateway_name about.resource.attribute.labels [resource_gateway_name]

What's next