Detection rules › Splunk

Windows Powershell Logoff User via Quser

Status
production
Severity
low
Group by
Guid, Name, Opcode, Path, ScriptBlockId, ScriptBlockText, dest, process_id, signature, signature_id, user_id, vendor_product
Author
Teoderick Contreras, Splunk
Source
github.com/splunk/security_content

The following analytic detects the process of logging off a user through the use of the quser and logoff commands. By monitoring for these commands, the analytic identifies actions where a user session is forcibly terminated, which could be part of an administrative task or a potentially unauthorized access attempt. This detection helps identify potential misuse or malicious activity where a user's access is revoked without proper authorization, providing insight into potential security incidents involving account management or session manipulation.

Known false positives

  • Administrators or power users may use this command.

MITRE ATT&CK coverage

Telemetry coverage

Rule body

name: Windows Powershell Logoff User via Quser
id: 6d70780d-4cfe-4820-bafd-1b43941986b5
version: 9
creation_date: '2024-12-13'
modification_date: '2026-06-29'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: |-
    The following analytic detects the process of logging off a user through the use of the quser and logoff commands.
    By monitoring for these commands, the analytic identifies actions where a user session is forcibly terminated, which could be part of an administrative task or a potentially unauthorized access attempt.
    This detection helps identify potential misuse or malicious activity where a user's access is revoked without proper authorization, providing insight into potential security incidents involving account management or session manipulation.
data_source:
    - Powershell Script Block Logging 4104
search: |-
    `powershell`
    EventCode=4104
    ScriptBlockText = "*quser*logoff*"
    | fillnull
    | stats count min(_time) as firstTime
                  max(_time) as lastTime
      by dest signature signature_id
         user_id vendor_product EventID
         Guid Opcode Name
         Path ProcessID ScriptBlockId
         ScriptBlockText
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_powershell_logoff_user_via_quser_filter`
how_to_implement: The following Hunting analytic requires PowerShell operational logs to be imported. Modify the powershell macro as needed to match the sourcetype or add index. This analytic is specific to 4104, or PowerShell Script Block Logging.
known_false_positives: Administrators or power users may use this command.
references:
    - https://devblogs.microsoft.com/scripting/automating-quser-through-powershell/
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: A suspicious powershell script with the ScriptBlockId [$ScriptBlockId$] containing quser and logoff commands to potentially logoff user was executed on host $dest$
        - field: user_id
          type: user
          score: 20
          message: A suspicious powershell script with the ScriptBlockId [$ScriptBlockId$] containing quser and logoff commands to potentially logoff user was executed on host $dest$ by user $user_id$
analytic_story:
    - Crypto Stealer
asset_type: Endpoint
mitre_attack_id:
    - T1059.001
    - T1531
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint

Stages and Predicates

Stage 1: search

`powershell`
EventCode=4104
ScriptBlockText = "*quser*logoff*"

Stage 2: fillnull

| fillnull

Stage 3: stats

| stats count min(_time) as firstTime
              max(_time) as lastTime
  by dest signature signature_id
     user_id vendor_product EventID
     Guid Opcode Name
     Path ProcessID ScriptBlockId
     ScriptBlockText

Stage 4: search

| `security_content_ctime(firstTime)`

Stage 5: search

| `security_content_ctime(lastTime)`

Stage 6: search

| `windows_powershell_logoff_user_via_quser_filter`

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
EventCodeeq
  • 4104 corpus 269 (splunk 269)
field:"EventID" kind:eq value:"4104"
ScriptBlockTexteq
  • "*quser*logoff*"
field:"ScriptBlockText" kind:eq