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Description

This analytic detects a potential suspicious modification of firewall rule registry allowing inbound traffic in specific port with public profile. This technique was identified when an adversary wants to grant remote access to a machine by allowing the traffic in a firewall rule.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-05-26
  • Author: Teoderick Contreras, Splunk
  • ID: 0a46537c-be02-11eb-92ca-acde48001122

ATT&CK

ID Technique Tactic
T1021.001 Remote Desktop Protocol Lateral Movement

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Registry where Registry.registry_path= "*\\System\\CurrentControlSet\\Services\\SharedAccess\\Parameters\\FirewallPolicy\\FirewallRules\\*" Registry.registry_value_name = "*
|Action=Allow
|*" Registry.registry_value_name = "*
|Dir=In
|*" Registry.registry_value_name = "*
|Profile=Public
|*" Registry.registry_value_name = "*
|LPort=*" by Registry.registry_path Registry.registry_key_name Registry.user Registry.registry_value_name Registry.dest 
| `drop_dm_object_name(Registry)` 
| `security_content_ctime(firstTime)` 
|`security_content_ctime(lastTime)` 
| `allow_inbound_traffic_by_firewall_rule_registry_filter`

Associated Analytic Story

How To Implement

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Registry node. Also make sure that this registry was included in your config files ex. sysmon config to be monitored.

Required field

  • _time
  • Registry.registry_path
  • Registry.registry_value_name
  • Registry.registry_key_name
  • Registry.dest
  • Registry.user

Kill Chain Phase

  • Exploitation

Known False Positives

network admin may add/remove/modify public inbound firewall rule that may cause this rule to be triggered.

RBA

Risk Score Impact Confidence Message
3.0 10 30 Suspicious firewall modifications were detected via the registry on endpoint $dest$ by user $user$.

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

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