[New Rule] GCP Virtual Private Cloud Network Deleted (#325)

* [New Rule] GCP Virtual Private Cloud Network Deleted

* Update rule name to align with other rules

Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com>

Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com>

rules/gcp/impact_gcp_virtual_private_cloud_network_deleted.toml

@@ -0,0 +1,35 @@
+[metadata]
+creation_date = "2020/09/22"
+ecs_version = ["1.6.0"]
+maturity = "production"
+updated_date = "2020/09/22"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies when a Virtual Private Cloud (VPC) network is deleted in Google Cloud Platform (GCP). A VPC network is a
+virtual version of a physical network within a GCP project. Each VPC network has its own subnets, routes, and firewall,
+as well as other elements. An adversary may delete a VPC network in order to disrupt their target's network and business
+operations.
+"""
+false_positives = [
+    """
+    Virtual Private Cloud networks may be deleted by system administrators. Verify that the configuration change was
+    expected. Exceptions can be added to this rule to filter expected behavior.
+    """,
+]
+index = ["filebeat-*"]
+language = "kuery"
+license = "Elastic License"
+name = "GCP Virtual Private Cloud Network Deletion"
+note = "The GCP Filebeat module must be enabled to use this rule."
+references = ["https://cloud.google.com/vpc/docs/vpc"]
+risk_score = 47
+rule_id = "c58c3081-2e1d-4497-8491-e73a45d1a6d6"
+severity = "medium"
+tags = ["Elastic", "GCP", "Continuous Monitoring", "SecOps", "Configuration Audit"]
+type = "query"
+
+query = '''
+event.module:googlecloud and event.dataset:googlecloud.audit and event.action:v*.compute.networks.delete and event.outcome:success
+'''