Startup/Logon Script added to Group Policy Objectedit

Detects the modification of Group Policy Objects (GPO) to add a startup/logon script to users or computer objects.

Rule type: query

Rule indices:

  • winlogbeat-*
  • logs-system.*

Severity: medium

Risk score: 47

Runs every: 5 minutes

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100



  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Privilege Escalation
  • Active Directory
  • Investigation Guide

Version: 102 (version history)

Added (Elastic Stack release): 8.0.0

Last modified (Elastic Stack release): 8.6.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positivesedit

Legitimate Administrative Activity

Investigation guideedit

## Triage and analysis

### Investigating Scheduled Task Execution at Scale via GPO

Group Policy Objects (GPOs) can be used by attackers to instruct arbitrarily large groups of
clients to execute specified commands at startup, logon, shutdown, and logoff. This is done by creating or modifying the
`scripts.ini` or `psscripts.ini` files. The scripts are stored in the following path: `<GPOPath>\Machine\Scripts\`,

#### Possible investigation steps

- This attack abuses a legitimate mechanism of Active Directory, so it is important to determine whether the activity
is legitimate and the administrator is authorized to perform this operation.
- Retrieve the contents of the `ScheduledTasks.xml` file, and check the `<Command>` and `<Arguments>` XML tags for any
potentially malicious commands or binaries.
- Investigate other alerts associated with the user/host during the past 48 hours.
- Scope which objects may be compromised by retrieving information about which objects are controlled by the GPO.

### False positive analysis

- Verify if the execution is legitimately authorized and executed under a change management process.

### Related rules

- Group Policy Abuse for Privilege Addition - b9554892-5e0e-424b-83a0-5aef95aa43bf
- Scheduled Task Execution at Scale via GPO - 15a8ba77-1c13-4274-88fe-6bd14133861e

### Response and remediation

- Initiate the incident response process based on the outcome of the triage.
- The investigation and containment must be performed in every computer controlled by the GPO, where necessary.
- Remove the script from the GPO.
- Check if other GPOs have suspicious scripts attached.
- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
- Using the incident response data, update logging and audit policies to improve the mean time to detect (MTTD) and the
mean time to respond (MTTR).

Rule queryedit

( event.code:5136 and
or gPCUserExtensionNames) and winlog.event_data.AttributeValue:(*42
B5FAAE-6536-11D2-AE5A-0000F87571E3* and
(*40B66650-4972-11D1-A7CA-0000F87571E3* or
*40B6664F-4972-11D1-A7CA-0000F87571E3*)) ) or ( event.code:5145 and
winlog.event_data.ShareName:\\\\*\\SYSVOL and
winlog.event_data.RelativeTargetName:(*\\scripts.ini or
*\\psscripts.ini) and (message:WriteData or
winlog.event_data.AccessList:*%%4417*) )

Threat mappingedit


Rule version historyedit

Version 102 (8.6.0 release)
  • Formatting only
Version 101 (8.5.0 release)
  • Formatting only
Version 6 (8.4.0 release)
  • Formatting only
Version 4 (8.3.0 release)
  • Formatting only
Version 3 (8.2.0 release)
  • Formatting only
Version 2 (8.1.0 release)
  • Formatting only