Windows System Discovery Using ldap Nslookup

SPLUNK detection rule by Teoderick Contreras, Splunk · Apache-2.0

The following analytic detects the execution of nslookup.exe to query domain information using LDAP. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and command-line arguments. This activity is significant as nslookup.exe can be abused by malware like Qakbot to gather critical domain details, such as SRV records and server names. If confirmed malicious, this behavior could allow attackers to map the network, identify key servers, and plan further attacks, potentially leading to data exfiltration or lateral movement within the network.

name: Windows System Discovery Using ldap Nslookup
id: 2418780f-7c3e-4c45-b8b4-996ea850cd49
version: 10
creation_date: '2022-10-21'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects the execution of nslookup.exe to query domain information using LDAP. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and command-line arguments. This activity is significant as nslookup.exe can be abused by malware like Qakbot to gather critical domain details, such as SRV records and server names. If confirmed malicious, this behavior could allow attackers to map the network, identify key servers, and plan further attacks, potentially leading to data exfiltration or lateral movement within the network.
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_name = "nslookup.exe"
            OR
            Processes.original_file_name = "nslookup.exe"
        )
        AND Processes.process = "*_ldap._tcp.dc._msdcs*"
      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_system_discovery_using_ldap_nslookup_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: dministrator may execute this commandline tool for auditing purposes. Filter as needed.
references:
    - https://securelist.com/qakbot-technical-analysis/103931/
    - https://learn.microsoft.com/en-us/troubleshoot/windows-server/networking/verify-srv-dns-records-have-been-created
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"
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: System nslookup domain discovery on $dest$
analytic_story:
    - Qakbot
asset_type: Endpoint
mitre_attack_id:
    - T1033
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/T1033/qakbot_discovery_cmdline/sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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23db2cc1-580b-498d-9db8-7bc3c63c8d30

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