Outbound Network Connection from Java Using Default Ports

name: Outbound Network Connection from Java Using Default Ports
id: d2c14d28-5c47-11ec-9892-acde48001122
version: 11
date: '2026-03-18'
author: Mauricio Velazco, Lou Stella, Splunk
status: production
type: TTP
description: |
    The following analytic detects outbound network connections from Java processes to default ports used by LDAP and RMI protocols, which may indicate exploitation of the CVE-2021-44228-Log4j vulnerability.
    This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process and network traffic logs.
    Monitoring this activity is crucial as it can signify an attacker's attempt to perform JNDI lookups and retrieve malicious payloads.
    If confirmed malicious, this activity could lead to remote code execution and further compromise of the affected server.
data_source:
    - Sysmon EventID 1 AND Sysmon EventID 3
search: |-
    | tstats `security_content_summariesonly` count
    FROM datamodel=Endpoint.Processes WHERE

    Processes.process_name IN (
        "java.exe",
        "javaw.exe"
    )
    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)`
    | join process_id
    [
        | tstats `security_content_summariesonly` count
        FROM datamodel=Network_Traffic.All_Traffic WHERE
        All_Traffic.dest_port IN (
                    389,
                    636,
                    1099,
                    1389
        )
        BY All_Traffic.action All_Traffic.app All_Traffic.bytes
            All_Traffic.bytes_in All_Traffic.bytes_out All_Traffic.dest
            All_Traffic.dest_ip All_Traffic.dest_port All_Traffic.dvc
            All_Traffic.protocol All_Traffic.protocol_version All_Traffic.src
            All_Traffic.src_ip All_Traffic.src_port All_Traffic.transport
            All_Traffic.user All_Traffic.vendor_product All_Traffic.direction
            All_Traffic.process_id
        | `drop_dm_object_name(All_Traffic)`
        | rename dest as connection_to_CNC
    ]
    | table _time dest
            parent_process_path parent_process_name parent_process
            process_path process_name process process_hash
            connection_to_CNC dest_port user
    | `outbound_network_connection_from_java_using_default_ports_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: |
    Legitimate Java applications may use perform outbound connections to these ports. Filter as needed
references:
    - https://www.lunasec.io/docs/blog/log4j-zero-day/
    - https://www.govcert.admin.ch/blog/zero-day-exploit-targeting-popular-java-library-log4j/
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 ("$dest$") 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: $info_max_time$
rba:
    message: Java performed outbound connections to default ports of LDAP or RMI on $dest$
    risk_objects:
        - field: dest
          type: system
          score: 50
    threat_objects: []
tags:
    analytic_story:
        - Log4Shell CVE-2021-44228
    asset_type: Endpoint
    cve:
        - CVE-2021-44228
    mitre_attack_id:
        - T1190
        - T1133
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1190/outbound_java/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog