> For the complete documentation index, see [llms.txt](https://cortex-docs.paloaltonetworks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cortex-docs.paloaltonetworks.com/appsec-rules/iac-security/logging/appsec-gcp-26.md).

# GCP VPC Flow logs for the subnet is set to Off misconfiguration detected in code

## Rule Details

|                        |                                      |
| ---------------------- | ------------------------------------ |
| Cortex AppSec Rule ID  | APPSEC\_GCP\_26                      |
| Category - Subcategory | Logging - Disabled or missing        |
| Provider               | GCP                                  |
| Severity               | LOW                                  |
| Framework              | Terraform, Terraform Plan            |
| Mapped CSPM/KSPM Rule  | 4e0039a6-ead7-4a28-8041-ef4889c312df |

## Impact

Flow Logs capture information about IP traffic going to and from network interfaces. This information can be used to detect anomalous traffic and insight about security workflows. You can view and retrieve flow log data in Stackdriver Logging. VPC networks and subnetworks provide logically isolated and secure network partitions to launch Google Cloud Platform (GCP) resources. When Flow Logs are enabled for a subnet, VMs within that subnet report on all Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) flows. Each VM samples the inbound and outbound TCP and UDP flows it sees, whether the flow is to or from another VM, a host in the on-premises datacenter, a Google service, or a host on the Internet. If two GCP VMs are communicating and both are in subnets that have VPC Flow Logs enabled, both VMs report the flows. We recommended you set *Flow Logs* to *On* to capture this data. Because the volume of logs may be high, you may wish to enable flow logs only for business-critical VPC Network Subnets. Flow Logs supports the following use cases:

* Network monitoring
* Understanding network usage and optimizing network traffic expenses
* Network forensics
* Real-time security analysis

## How to Fix

*Resource:* google\_compute\_subnetwork

* *Arguments:* log\_config \[source,go]

***

resource "google\_compute\_subnetwork" "example" { name = "log-test-subnetwork" ip\_cidr\_range = "10.2.0.0/16" region = "us-central1" network = google\_compute\_network.custom-test.id

* log\_config { aggregation\_interval = "INTERVAL\_10\_MIN" flow\_sampling = 0.5 metadata = "INCLUDE\_ALL\_METADATA" } }

***


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