Detection rules › Splunk

RunDLL Loading DLL By Ordinal

Status
production
Severity
medium
Group by
IntegrityLevel, command_line, computer_name, event_action, original_file_name, parent_command_line, parent_process_guid, parent_process_id, parent_process_name, process_guid, process_hash, process_id, process_name, user, user_id, vendor_product
Author
Michael Haag, David Dorsey, Splunk
Source
github.com/splunk/security_content

The following analytic detects rundll32.exe loading a DLL export function by ordinal value. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process command-line executions. This behavior is significant because adversaries may use rundll32.exe to execute malicious code while evading security tools that do not monitor this process. If confirmed malicious, this activity could allow attackers to execute arbitrary code, potentially leading to system compromise, privilege escalation, or persistent access within the environment.

MITRE ATT&CK coverage

Event coverage

Rule body splunk

name: RunDLL Loading DLL By Ordinal
id: 6c135f8d-5e60-454e-80b7-c56eed739833
version: 16
creation_date: '2019-10-16'
modification_date: '2026-05-13'
author: Michael Haag, David Dorsey, Splunk
status: production
type: TTP
description: The following analytic detects rundll32.exe loading a DLL export function by ordinal value. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process command-line executions. This behavior is significant because adversaries may use rundll32.exe to execute malicious code while evading security tools that do not monitor this process. If confirmed malicious, this activity could allow attackers to execute arbitrary code, potentially leading to system compromise, privilege escalation, or persistent access within the environment.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |-
    | tstats `security_content_summariesonly` values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
      WHERE `process_rundll32`
      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)`
    | where match(process,"rundll32.+\#\d+")
    | `rundll_loading_dll_by_ordinal_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: False positives are possible with native utilities and third party applications. Filtering may be needed based on command-line, or add world writeable paths to restrict query.
references:
    - https://thedfirreport.com/2022/02/07/qbot-likes-to-move-it-move-it/
    - https://twitter.com/M_haggis/status/1491109262428635136
    - https://twitter.com/pr0xylife/status/1590394227758104576
drilldown_searches:
    - name: View the detection results for - "$dest$" and "$user$"
      search: '%original_detection_search% | search  dest = "$dest$" user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$" and "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$user$") | 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"
finding:
    title: A rundll32 process $process_name$ with ordinal parameter like this process commandline $process$ on host $dest$.
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: A rundll32 process $process_name$ with ordinal parameter like this process commandline $process$ on host $dest$.
analytic_story:
    - Unusual Processes
    - Suspicious Rundll32 Activity
    - Living Off The Land
    - IcedID
asset_type: Endpoint
mitre_attack_id:
    - T1218.011
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/T1218.011/atomic_red_team/ordinal_windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly` values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
  WHERE `process_rundll32`
  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

Stage 2: search

| `drop_dm_object_name(Processes)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: where

| where match(process,"rundll32.+\#\d+")

Stage 6: search

| `rundll_loading_dll_by_ordinal_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Processes.original_file_nameeq
  • "RUNDLL32.EXE" corpus 62 (sigma 35, splunk 21, elastic 6)
Processes.process_nameeq
  • "rundll32.exe" corpus 60 (elastic 34, splunk 26)
processmatch
  • "rundll32.+\#\d+"