Detection rules › Splunk

Malicious Powershell Executed As A Service

Status
production
Severity
medium
Group by
ImagePath, ServiceType, StartType, dest, service_name, signature_id, user
Author
Ryan Becwar
Source
github.com/splunk/security_content

The following analytic identifies the execution of malicious PowerShell commands or payloads via the Windows SC.exe utility. It detects this activity by analyzing Windows System logs (EventCode 7045) and filtering for specific PowerShell-related patterns in the ImagePath field. This behavior is significant because it indicates potential abuse of the Windows Service Control Manager to run unauthorized or harmful scripts, which could lead to system compromise. If confirmed malicious, this activity could allow attackers to execute arbitrary code, escalate privileges, or maintain persistence within the environment.

MITRE ATT&CK coverage

Event coverage

Rule body splunk

name: Malicious Powershell Executed As A Service
id: 8e204dfd-cae0-4ea8-a61d-e972a1ff2ff8
version: 13
creation_date: '2021-04-13'
modification_date: '2026-05-13'
author: Ryan Becwar
status: production
type: TTP
description: The following analytic identifies the execution of malicious PowerShell commands or payloads via the Windows SC.exe utility. It detects this activity by analyzing Windows System logs (EventCode 7045) and filtering for specific PowerShell-related patterns in the ImagePath field. This behavior is significant because it indicates potential abuse of the Windows Service Control Manager to run unauthorized or harmful scripts, which could lead to system compromise. If confirmed malicious, this activity could allow attackers to execute arbitrary code, escalate privileges, or maintain persistence within the environment.
data_source:
    - Windows Event Log System 7045
search: |-
    `wineventlog_system`
    EventCode=7045
    | eval l_ImagePath=lower(ImagePath)
    | regex l_ImagePath="powershell[.\s]|powershell_ise[.\s]|pwsh[.\s]|psexec[.\s]"
    | regex l_ImagePath="-nop[rofile\s]+|-w[indowstyle]*\s+hid[den]*|-noe[xit\s]+|-enc[odedcommand\s]+"
    | stats count min(_time) as firstTime max(_time) as lastTime
        by EventCode ImagePath ServiceName StartType
           ServiceType AccountName UserID dest
    | rename UserID as user
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `malicious_powershell_executed_as_a_service_filter`
how_to_implement: To successfully implement this search, you need to be ingesting Windows System logs with the Service name, Service File Name Service Start type, and Service Type from your endpoints.
known_false_positives: Creating a hidden powershell service is rare and could key off of those instances.
references:
    - https://www.fireeye.com/content/dam/fireeye-www/blog/pdfs/dosfuscation-report.pdf
    - http://az4n6.blogspot.com/2017/
    - https://www.danielbohannon.com/blog-1/2017/3/12/powershell-execution-argument-obfuscation-how-it-can-make-detection-easier
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: Identifies the abuse the Windows SC.exe to execute malicious powerShell as a service $ImagePath$ by $user$ on $dest$
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: Identifies the abuse the Windows SC.exe to execute malicious powerShell as a service $ImagePath$ by $user$ on $dest$
analytic_story:
    - Compromised Windows Host
    - Rhysida Ransomware
    - Malicious PowerShell
asset_type: Endpoint
mitre_attack_id:
    - T1569.002
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/T1569.002/malicious_powershell_executed_as_a_service/windows-xml.log
          source: XmlWinEventLog:System
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: search

`wineventlog_system`
EventCode=7045

Stage 2: eval

| eval l_ImagePath=lower(ImagePath)

Stage 3: regex

| regex l_ImagePath="powershell[.\s]|powershell_ise[.\s]|pwsh[.\s]|psexec[.\s]"

Stage 4: regex

| regex l_ImagePath="-nop[rofile\s]+|-w[indowstyle]*\s+hid[den]*|-noe[xit\s]+|-enc[odedcommand\s]+"

Stage 5: stats

| stats count min(_time) as firstTime max(_time) as lastTime
    by EventCode ImagePath ServiceName StartType
       ServiceType AccountName UserID dest

Stage 6: rename

| rename UserID as user

Stage 7: search

| `security_content_ctime(firstTime)`

Stage 8: search

| `security_content_ctime(lastTime)`

Stage 9: search

| `malicious_powershell_executed_as_a_service_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
EventCodeeq
  • 7045 corpus 20 (splunk 18, chronicle 1, kusto 1)
l_ImagePathregex_match
    • "-nop[rofile\s]+
    • -w[indowstyle]*\s+hid[den]*
    • -noe[xit\s]+
    • -enc[odedcommand\s]+"
    • "powershell[.\s]
    • powershell_ise[.\s]
    • pwsh[.\s]
    • psexec[.\s]"