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Description

The following analytic is to identify a modification in the Windows firewall to enable remote desktop protocol on a targeted machine. This technique was seen in several adversaries, malware or red teamer to remotely access the compromised or targeted host by allowing this protocol in firewall. Even this protocol might be allowed in some production environment, This TTP behavior is a good pivot to check who and why the user want to enable this feature through firewall which is also common traits of attack to start lateral movement.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2022-06-21
  • Author: Teoderick Contreras, Splunk
  • ID: 9170cb54-ea15-41e1-9dfc-9f3363ce9b02

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1021.001 Remote Desktop Protocol Lateral Movement
T1021 Remote Services Lateral Movement
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE
1
2
3
4
5
6
| tstats `security_content_summariesonly` values(Processes.process) as cmdline values(Processes.parent_process_name) as parent_process values(Processes.process_name) count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_name = "netsh.exe" OR Processes.original_file_name= "netsh.exe") AND Processes.process = "*firewall*" AND Processes.process = "*add*" AND Processes.process = "*protocol=TCP*" AND Processes.process = "*localport=3389*" AND Processes.process = "*action=allow*" by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_remote_services_allow_rdp_in_firewall_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_remote_services_allow_rdp_in_firewall_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • Processes.process_name
  • Processes.process
  • Processes.parent_process_name
  • Processes.parent_process
  • Processes.process_id
  • Processes.parent_process_id
  • Processes.dest
  • Processes.user

How To Implement

To successfully implement this search, you must be ingesting data that records process activity from your hosts to populate the endpoint data model in the processes node. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Known False Positives

administrators may enable or disable this feature that may cause some false positive.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
49.0 70 70 new firewall rules was added to allow rdp connection to $dest$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 1