[New Rule] Potential Remote Desktop Tunneling Detected (#374)

* [New Rule] Remote Desktop Tunneling using SSH Plink Utility

* Update lateral_movement_rdp_tunnel_plink.toml

* Update lateral_movement_rdp_tunnel_plink.toml

* changed tags

* expanded condition to more than plink

there are other SSH utilities that can be used as Plink thus removed the process original filename condition and added mandatory switches such as -L -P and -R.

* Update lateral_movement_rdp_tunnel_plink.toml

* more args options

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

rules/windows/lateral_movement_rdp_tunnel_plink.toml

@@ -0,0 +1,44 @@
+[metadata]
+creation_date = "2020/10/14"
+ecs_version = ["1.6.0"]
+maturity = "production"
+updated_date = "2020/10/14"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies potential use of an SSH utility to establish RDP over a reverse SSH Tunnel. This could be indicative of adversary lateral
+movement to interactively access restricted networks.
+"""
+from = "now-9m"
+index = ["logs-endpoint.events.*", "winlogbeat-*"]
+language = "eql"
+license = "Elastic License"
+name = "Potential Remote Desktop Tunneling Detected"
+references = ["https://blog.netspi.com/how-to-access-rdp-over-a-reverse-ssh-tunnel/"]
+risk_score = 73
+rule_id = "76fd43b7-3480-4dd9-8ad7-8bd36bfad92f"
+severity = "high"
+tags = ["Elastic", "Host", "Windows", "Threat Detection", "Lateral Movement"]
+type = "eql"
+
+query = '''
+process where event.type in ("start", "process_started", "info") and 
+/* RDP port and usual SSH tunneling related switches in commandline */
+wildcard(process.args, "*:3389") and wildcard(process.args,"-L", "-P", "-R", "-pw", "-ssh") 
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1021"
+name = "Remote Services"
+reference = "https://attack.mitre.org/techniques/T1021/"
+
+
+[rule.threat.tactic]
+id = "TA0008"
+name = "Lateral Movement"
+reference = "https://attack.mitre.org/tactics/TA0008/"
+