Detection rules › Splunk
WinEvent Scheduled Task Created to Spawn Shell
The following analytic detects the creation of scheduled tasks designed to execute commands using native Windows shells like PowerShell, Cmd, Wscript, or Cscript. It leverages Windows Security EventCode 4698 to identify when such tasks are registered. This activity is significant as it may indicate an attempt to establish persistence or execute malicious commands on a system. If confirmed malicious, this could allow an attacker to maintain access, execute arbitrary code, or escalate privileges, posing a severe threat to the environment.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | T1053.005 Scheduled Task/Job: Scheduled Task |
| Persistence | T1053.005 Scheduled Task/Job: Scheduled Task |
| Privilege Escalation | T1053.005 Scheduled Task/Job: Scheduled Task |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4698 | A scheduled task was created. |
Rule body splunk
name: WinEvent Scheduled Task Created to Spawn Shell
id: 203ef0ea-9bd8-11eb-8201-acde48001122
version: 20
creation_date: '2021-04-08'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic detects the creation of scheduled tasks designed to execute commands using native Windows shells like PowerShell, Cmd, Wscript, or Cscript. It leverages Windows Security EventCode 4698 to identify when such tasks are registered. This activity is significant as it may indicate an attempt to establish persistence or execute malicious commands on a system. If confirmed malicious, this could allow an attacker to maintain access, execute arbitrary code, or escalate privileges, posing a severe threat to the environment.
data_source:
- Windows Event Log Security 4698
search: |-
`wineventlog_security` EventCode=4698 TaskContent IN ("*powershell.exe*", "*wscript.exe*", "*cscript.exe*", "*cmd.exe*", "*sh.exe*", "*ksh.exe*", "*zsh.exe*", "*bash.exe*", "*scrcons.exe*", "*pwsh.exe*")
| stats count min(_time) as firstTime max(_time) as lastTime
BY Computer, TaskName, TaskContent
| rename Computer as dest
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `winevent_scheduled_task_created_to_spawn_shell_filter`
how_to_implement: To successfully implement this search, you need to be ingesting Windows Security Event Logs with 4698 EventCode enabled. The Windows TA is also required.
known_false_positives: False positives are possible if legitimate applications are allowed to register tasks that call a shell to be spawned. Filter as needed based on command-line or processes that are used legitimately.
references:
- https://research.checkpoint.com/2021/irans-apt34-returns-with-an-updated-arsenal/
- https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventID=4698
- https://redcanary.com/threat-detection-report/techniques/scheduled-task-job/
- https://docs.microsoft.com/en-us/windows/win32/taskschd/time-trigger-example--scripting-?redirectedfrom=MSDN
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 Windows Scheduled Task was created (task name=$TaskName$) on $dest$ with the following contents: $TaskContent$'
entity:
field: dest
type: system
score: 50
analytic_story:
- CISA AA22-257A
- China-Nexus Threat Activity
- Compromised Windows Host
- Medusa Ransomware
- Ransomware
- Ryuk Ransomware
- Salt Typhoon
- Scheduled Tasks
- SystemBC
- Windows Error Reporting Service Elevation of Privilege Vulnerability
- Windows Persistence Techniques
- Winter Vivern
- 0bj3ctivity Stealer
- Castle RAT
asset_type: Endpoint
mitre_attack_id:
- T1053.005
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/T1053.005/winevent_scheduled_task_created_to_spawn_shell/windows-xml.log
source: XmlWinEventLog:Security
sourcetype: XmlWinEventLog
test_type: unit
Stages and Predicates
Stage 1: search
`wineventlog_security` EventCode=4698 TaskContent IN ("*powershell.exe*", "*wscript.exe*", "*cscript.exe*", "*cmd.exe*", "*sh.exe*", "*ksh.exe*", "*zsh.exe*", "*bash.exe*", "*scrcons.exe*", "*pwsh.exe*")
Stage 2: stats
| stats count min(_time) as firstTime max(_time) as lastTime
BY Computer, TaskName, TaskContent
Stage 3: rename
| rename Computer as dest
Stage 4: search
| `security_content_ctime(firstTime)`
Stage 5: search
| `security_content_ctime(lastTime)`
Stage 6: search
| `winevent_scheduled_task_created_to_spawn_shell_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.
| Field | Kind | Values |
|---|---|---|
EventCode | eq |
|
TaskContent | in |
|