[New Rule] AWS Root Login Without MFA

Co-authored-by: Derek Ditch <dcode@users.noreply.github.com>
Co-authored-by: David French <56409778+threat-punter@users.noreply.github.com>

rules/aws/privilege_escalation_root_login_without_mfa.toml

@@ -0,0 +1,48 @@
+[metadata]
+creation_date = "2020/07/06"
+ecs_version = ["1.5.0"]
+maturity = "production"
+updated_date = "2020/07/07"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies attempts to login to AWS as the root user without using multi-factor authentication (MFA). Amazon AWS best
+practices indicate that the root user should be protected by MFA.
+"""
+false_positives = [
+    """
+    Some organizations allow login with the root user without MFA, however this is not considered best practice by AWS
+    and increases the risk of compromised credentials.
+    """,
+]
+from = "now-20m"
+index = ["filebeat-*"]
+interval = "10m"
+language = "kuery"
+license = "Elastic License"
+name = "AWS Root Login Without MFA"
+references = ["https://docs.aws.amazon.com/IAM/latest/UserGuide/id_root-user.html"]
+risk_score = 21
+rule_id = "bc0c6f0d-dab0-47a3-b135-0925f0a333bc"
+severity = "low"
+tags = ["AWS", "Elastic"]
+type = "query"
+
+query = '''
+event.module:aws and event.dataset:aws.cloudtrail and event.provider:signin.amazonaws.com and event.action:ConsoleLogin and aws.cloudtrail.user_identity.type:Root and aws.cloudtrail.console_login.additional_eventdata.mfa_used:false and event.outcome:success
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1078"
+name = "Valid Accounts"
+reference = "https://attack.mitre.org/techniques/T1078/"
+
+
+[rule.threat.tactic]
+id = "TA0004"
+name = "Privilege Escalation"
+reference = "https://attack.mitre.org/tactics/TA0004/"