Detection rules › Splunk
Schedule Task with Rundll32 Command Trigger
The following analytic detects the creation of scheduled tasks in Windows that use the rundll32 command. It leverages Windows Security EventCode 4698, which logs the creation of scheduled tasks, and filters for tasks executed via rundll32. This activity is significant as it is a common technique used by malware, such as TrickBot, to persist in an environment or deliver additional payloads. If confirmed malicious, this could lead to data theft, ransomware deployment, or other damaging outcomes. Immediate investigation and mitigation are crucial to prevent further compromise.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | T1053 Scheduled Task/Job |
| Persistence | T1053 Scheduled Task/Job |
| Privilege Escalation | T1053 Scheduled Task/Job |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4698 | A scheduled task was created. |
Rule body splunk
name: Schedule Task with Rundll32 Command Trigger
id: 75b00fd8-a0ff-11eb-8b31-acde48001122
version: 12
creation_date: '2021-04-26'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: The following analytic detects the creation of scheduled tasks in Windows that use the rundll32 command. It leverages Windows Security EventCode 4698, which logs the creation of scheduled tasks, and filters for tasks executed via rundll32. This activity is significant as it is a common technique used by malware, such as TrickBot, to persist in an environment or deliver additional payloads. If confirmed malicious, this could lead to data theft, ransomware deployment, or other damaging outcomes. Immediate investigation and mitigation are crucial to prevent further compromise.
data_source:
- Windows Event Log Security 4698
search: |-
`wineventlog_security` EventCode=4698
| xmlkv Message
| search Command IN ("*rundll32*")
| stats count min(_time) as firstTime max(_time) as lastTime
BY dest, Task_Name, Command,
Author, Enabled, Hidden,
Arguments
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `schedule_task_with_rundll32_command_trigger_filter`
how_to_implement: To successfully implement this search, you need to be ingesting logs with the task schedule (Exa. Security Log EventCode 4698) endpoints. Tune and filter known instances of Task schedule used in your environment.
known_false_positives: No false positives have been identified at this time.
references:
- https://labs.vipre.com/trickbot-and-its-modules/
- https://whitehat.eu/incident-response-case-study-featuring-ryuk-and-trickbot-part-2/
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"
finding:
title: A scheduled task process commandline rundll32 arguments $Arguments$ on host $dest$
entity:
field: dest
type: system
score: 50
analytic_story:
- Windows Persistence Techniques
- Living Off The Land
- IcedID
- Scheduled Tasks
- Compromised Windows Host
- Trickbot
- Castle RAT
asset_type: Endpoint
mitre_attack_id:
- T1053
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/malware/trickbot/tasksched/windows-security.log
source: WinEventLog:Security
sourcetype: WinEventLog
test_type: unit
Stages and Predicates
Stage 1: search
`wineventlog_security` EventCode=4698
Stage 2: xmlkv
| xmlkv Message
Stage 3: search
| search Command IN ("*rundll32*")
Stage 4: stats
| stats count min(_time) as firstTime max(_time) as lastTime
BY dest, Task_Name, Command,
Author, Enabled, Hidden,
Arguments
Stage 5: search
| `security_content_ctime(firstTime)`
Stage 6: search
| `security_content_ctime(lastTime)`
Stage 7: search
| `schedule_task_with_rundll32_command_trigger_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.