Name:Allow Network Discovery In Firewall id:ccd6a38c-d40b-11eb-85a5-acde48001122 version:4 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic detects a suspicious modification to the firewall to allow network discovery on a machine. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions involving the 'netsh' command to enable network discovery. This activity is significant because it is commonly used by ransomware, such as REvil and RedDot, to discover and compromise additional machines on the network. If confirmed malicious, this could lead to widespread file encryption across multiple hosts, significantly amplifying the impact of the ransomware attack. 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 `process_netsh` Processes.process= "*firewall*" Processes.process= "*group=\"Network Discovery\"*" Processes.process="*enable*" Processes.process="*Yes*" by Processes.dest Processes.user Processes.parent_process Processes.original_file_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.parent_process_name | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `allow_network_discovery_in_firewall_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:network admin may modify this firewall feature that may cause this rule to be triggered. References: -https://community.fortinet.com:443/t5/FortiEDR/How-FortiEDR-detects-and-blocks-Revil-Ransomware-aka-sodinokibi/ta-p/189638?externalID=FD52469 -https://app.any.run/tasks/c0f98850-af65-4352-9746-fbebadee4f05/ drilldown_searches: name:'View the detection results for - "$user$"' search:'%original_detection_search% | search user = "$user$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$user$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$") 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: - 'Ransomware' - 'Revil Ransomware' - 'BlackByte Ransomware' - 'NjRAT' asset_type:Endpoint confidence:50 impact:50 message:Suspicious modification to the firewall to allow network discovery detected on host - $dest$ mitre_attack_id: - 'T1562.007' - 'T1562' observable: name:'user' type:'User' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'Processes.dest' - 'Processes.user' - 'Processes.parent_process_name' - 'Processes.parent_process' - 'Processes.original_file_name' - 'Processes.process_name' - 'Processes.process' - 'Processes.process_id' - 'Processes.parent_process_path' - 'Processes.process_path' - 'Processes.parent_process_id' risk_score:25.0 security_domain:endpoint
