Name:Internal Horizontal Port Scan id:1ff9eb9a-7d72-4993-a55e-59a839e607f1 version:3 date:2024-09-30 author:Dean Luxton status:production type:TTP Description:This analytic identifies instances where an internal host has attempted to communicate with 250 or more destination IP addresses using the same port and protocol. Horizontal port scans from internal hosts can indicate reconnaissance or scanning activities, potentially signaling malicious intent or misconfiguration. By monitoring network traffic logs, this detection helps detect and respond to such behavior promptly, enhancing network security and preventing potential threats. Data_source:
-AWS CloudWatchLogs VPCflow
search:| tstats `security_content_summariesonly` values(All_Traffic.action) as action values(All_Traffic.src_category) as src_category values(All_Traffic.dest_zone) as dest_zone values(All_Traffic.src_zone) as src_zone count from datamodel=Network_Traffic where All_Traffic.src_ip IN ("10.0.0.0/8","172.16.0.0/12","192.168.0.0/16") by All_Traffic.src_ip All_Traffic.dest_port All_Traffic.dest_ip span=1s _time All_Traffic.transport | `drop_dm_object_name("All_Traffic")` | eval gtime=_time | bin span=1h gtime | stats min(_time) as _time values(action) as action dc(dest_ip) as totalDestIPCount values(src_category) as src_category values(dest_zone) as dest_zone values(src_zone) as src_zone by src_ip dest_port gtime transport | where totalDestIPCount>=250 | eval dest_port=transport + "/" + dest_port | stats min(_time) as _time values(action) as action sum(totalDestIPCount) as totalDestIPCount values(src_category) as src_category values(dest_port) as dest_ports values(dest_zone) as dest_zone values(src_zone) as src_zone by src_ip gtime | fields - gtime | `internal_horizontal_port_scan_filter`
how_to_implement:To properly run this search, Splunk needs to ingest data from networking telemetry sources such as firewalls, NetFlow, or host-based networking events. Ensure that the Network_Traffic data model is populated to enable this search effectively. known_false_positives:Unknown References: drilldown_searches: name:'View the detection results for - "$src_ip$"' search:'%original_detection_search% | search src_ip = "$src_ip$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$src_ip$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$src_ip$") 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: - 'Network Discovery' asset_type:Endpoint confidence:80 impact:80 message:$src_ip$ has scanned for ports $dest_ports$ across $totalDestIPCount$ destination IPs mitre_attack_id: - 'T1046' observable: name:'src_ip' type:'Hostname' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' risk_score:64 required_fields: - '_time' - 'All_Traffic.action' - 'All_Traffic.src_ip' - 'All_Traffic.dest_ip' - 'All_Traffic.dest_port' security_domain:network
