[New Rule] GCP Logging Sink Deletion (#306)

* Create gcp_logging_sink_deletion.toml

* update description

* update rule name

rules/gcp/defense_evasion_gcp_logging_sink_deletion.toml

@@ -0,0 +1,50 @@
+[metadata]
+creation_date = "2020/09/18"
+ecs_version = ["1.6.0"]
+maturity = "production"
+updated_date = "2020/09/18"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies a Logging sink deletion in Google Cloud Platform (GCP). Every time a log entry arrives, Logging compares the
+log entry to the sinks in that resource. Each sink whose filter matches the log entry writes a copy of the log entry to
+the sink's export destination. An adversary may delete a Logging sink to evade detection.
+"""
+false_positives = [
+    """
+    Logging sink deletions may be done by a system or network administrator. Verify whether the user email, resource
+    name, and/or hostname should be making changes in your environment. Logging sink deletions from unfamiliar users or
+    hosts should be investigated. If known behavior is causing false positives, it can be exempted from the rule.
+    """,
+]
+index = ["filebeat-*"]
+language = "kuery"
+license = "Elastic License"
+name = "GCP Logging Sink Deletion"
+note = "The GCP Filebeat module must be enabled to use this rule."
+references = ["https://cloud.google.com/logging/docs/export"]
+risk_score = 47
+rule_id = "51859fa0-d86b-4214-bf48-ebb30ed91305"
+severity = "medium"
+tags = ["Elastic", "GCP", "Continuous Monitoring", "SecOps", "Logging"]
+type = "query"
+
+query = '''
+event.module:googlecloud and event.dataset:googlecloud.audit and event.action:google.logging.v*.ConfigServiceV*.DeleteSink and event.outcome:success
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1562"
+name = "Impair Defenses"
+reference = "https://attack.mitre.org/techniques/T1562/"
+
+
+[rule.threat.tactic]
+id = "TA0005"
+name = "Defense Evasion"
+reference = "https://attack.mitre.org/tactics/TA0005/"
+