[New Rule] Adding Detection for Multiple Okta Users with the Same Device Token Hash (#3267)

* added new rule 'Multiple Okta Users with the Same Device Token Hash'

* moved rule to okta integration folder

* adjusted query to be optimized

* added false positive comment

* Update rules/integrations/okta/initial_access_multiple_active_users_from_single_device.toml

rules/integrations/okta/initial_access_multiple_active_users_from_single_device.toml

@@ -0,0 +1,67 @@
+[metadata]
+creation_date = "2023/11/10"
+integration = ["okta"]
+maturity = "production"
+min_stack_comments = "Breaking change in Okta integration bumping version to ^2.0.0"
+min_stack_version = "8.10.0"
+updated_date = "2023/11/10"
+
+[rule]
+author = ["Elastic"]
+description = "Detects when Okta user or system events are reported for multiple users with the same device token hash."
+false_positives = [
+    "An Okta admnistrator may be logged into multiple accounts from the same host for legitimate reasons.",
+    "Users may share an endpoint related to work or personal use in which separate Okta accounts are used.",
+    "Shared systems such as Kiosks and conference room computers may be used by multiple users."
+]
+from = "now-9m"
+index = ["filebeat-*", "logs-okta*"]
+language = "kuery"
+license = "Elastic License v2"
+name = "Multiple Okta Users with the Same Device Token Hash"
+note = """## Setup
+The Okta Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule."""
+references = [
+    "https://developer.okta.com/docs/reference/api/system-log/",
+    "https://developer.okta.com/docs/reference/api/event-types/",
+    "https://www.elastic.co/security-labs/testing-okta-visibility-and-detection-dorothy",
+    "https://sec.okta.com/articles/2023/08/cross-tenant-impersonation-prevention-and-detection",
+]
+risk_score = 47
+rule_id = "50887ba8-7ff7-11ee-a038-f661ea17fbcd"
+severity = "medium"
+tags = ["Use Case: Identity and Access Audit", "Data Source: Okta", "Tactic: Initial Access"]
+timestamp_override = "event.ingested"
+type = "threshold"
+
+query = '''
+event.dataset:okta.system and not okta.actor.id:okta* and okta.debug_context.debug_data.dt_hash:* and okta.event_type:(system* or user*)
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1078"
+name = "Valid Accounts"
+reference = "https://attack.mitre.org/techniques/T1078/"
+[[rule.threat.technique.subtechnique]]
+id = "T1078.004"
+name = "Cloud Accounts"
+reference = "https://attack.mitre.org/techniques/T1078/004/"
+
+
+
+[rule.threat.tactic]
+id = "TA0001"
+name = "Initial Access"
+reference = "https://attack.mitre.org/tactics/TA0001/"
+
+[rule.threshold]
+field = ["okta.debug_context.debug_data.dt_hash"]
+value = 1
+[[rule.threshold.cardinality]]
+field = "okta.actor.id"
+value = 2
+
+