Name:Windows Modify Registry to Add or Modify Firewall Rule id:43254751-e2ce-409a-b6b4-4f851e8dcc26 version:4 date:2024-12-08 author:Teoderick Contreras, Splunk status:production type:Anomaly Description:The following analytic detects a potential addition or modification of firewall rules, signaling possible configuration changes or security policy adjustments. It tracks commands such as netsh advfirewall firewall add rule and netsh advfirewall firewall set rule, which may indicate attempts to alter network access controls. Monitoring these actions ensures the integrity of firewall settings and helps prevent unauthorized network access. Data_source:
-Sysmon EventID 12
-Sysmon EventID 13
-Sysmon EventID 14
search:| 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.action = modified BY Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.registry_value_data Registry.process_guid Registry.dest Registry.user Registry.action | `drop_dm_object_name(Registry)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_modify_registry_to_add_or_modify_firewall_rule_filter`
how_to_implement:To successfully implement this search, you need to be ingesting logs with the registry value name, registry path, and registry value data from your endpoints. If you are using Sysmon, you must have at least version 2.0 of the official Sysmon TA. https://splunkbase.splunk.com/app/5709 known_false_positives:network admin may add/remove/modify public inbound firewall rule that may cause this rule to be triggered. References: -https://www.bleepingcomputer.com/news/security/new-shrinklocker-ransomware-uses-bitlocker-to-encrypt-your-files/ drilldown_searches: name:'View the detection results for - "$user$" and "$dest$"' search:'%original_detection_search% | search user = "$user$" dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$user$" and "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") starthoursago=168 | 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:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'ShrinkLocker' - 'CISA AA24-241A' asset_type:Endpoint confidence:50 impact:50 message:firewall deletion found in registry in $dest$ mitre_attack_id: - 'T1112' observable: name:'user' type:'User' - role: - 'Victim' name:'dest' type:'Hostname' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'Registry.dest' - 'Registry.registry_value_name' - 'Registry.registry_key_name' - 'Registry.registry_path' - 'Registry.registry_value_data' - 'Registry.process_guid' - 'Registry.action' risk_score:25 security_domain:endpoint
