Windows Modify System Firewall with Notable Process Path

name: Windows Modify System Firewall with Notable Process Path
id: cd6d7410-9146-4471-a418-49edba6dadc4
version: 12
creation_date: '2021-11-17'
modification_date: '2026-05-13'
author: Teoderick Contreras, Will Metcalf, Splunk
status: production
type: TTP
description: The following analytic detects suspicious modifications to system firewall rules, specifically allowing execution of applications from notable and potentially malicious file paths. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions involving firewall rule changes. This activity is significant as it may indicate an adversary attempting to bypass firewall restrictions to execute malicious files. If confirmed malicious, this could allow attackers to execute unauthorized code, potentially leading to further system compromise, data exfiltration, or persistence within the environment.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process = "*firewall*" Processes.process = "*allow*" Processes.process = "*add*" Processes.process = "*ENABLE*" Processes.process IN ("*\\windows\\fonts\\*", "*\\windows\\temp\\*", "*\\users\\public\\*", "*\\windows\\debug\\*", "*\\Users\\Administrator\\Music\\*", "*\\Windows\\servicing\\*", "*\\Users\\Default\\*","*Recycle.bin*", "*\\Windows\\Media\\*", "\\Windows\\repair\\*", "*\\temp\\*", "*\\PerfLogs\\*") by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_modify_system_firewall_with_notable_process_path_filter`'
how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives: A network operator or systems administrator may utilize an automated or manual execution of this firewall rule that may generate false positives. Filter as needed.
references:
    - https://www.splunk.com/en_us/blog/security/more-than-just-a-rat-unveiling-njrat-s-mbr-wiping-capabilities.html
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: firewall allowed program commandline $process$ of $process_name$ on $dest$
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Medusa Ransomware
    - NjRAT
    - Compromised Windows Host
asset_type: Endpoint
mitre_attack_id:
    - T1686
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1562.004/njrat_add_firewall_rule/njrat_firewall_sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit