Windows BootLoader Inventory

SPLUNK detection rule by Michael Haag, Splunk · Apache-2.0

The following analytic identifies the bootloader paths on Windows endpoints. It leverages a PowerShell Scripted input to capture this data, which is then processed and aggregated using Splunk. Monitoring bootloader paths is significant for a SOC as it helps detect unauthorized modifications that could indicate bootkits or other persistent threats. If confirmed malicious, such activity could allow attackers to maintain persistence, bypass security controls, and potentially control the boot process, leading to full system compromise.

name: Windows BootLoader Inventory
id: 4f7e3913-4db3-4ccd-afe4-31198982305d
version: 8
creation_date: '2023-04-14'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: experimental
type: Hunting
description: The following analytic identifies the bootloader paths on Windows endpoints. It leverages a PowerShell Scripted input to capture this data, which is then processed and aggregated using Splunk. Monitoring bootloader paths is significant for a SOC as it helps detect unauthorized modifications that could indicate bootkits or other persistent threats. If confirmed malicious, such activity could allow attackers to maintain persistence, bypass security controls, and potentially control the boot process, leading to full system compromise.
data_source: []
search: |-
    `bootloader_inventory`
      | stats count min(_time) as firstTime max(_time) as lastTime values(_raw)
        BY host
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `windows_bootloader_inventory_filter`
how_to_implement: To implement this analytic, a new stanza will need to be added to a inputs.conf and deployed to all or some Windows endpoints. https://gist.github.com/MHaggis/26518cd2844b0e03de6126660bb45707 provides the stanza. If modifying the sourcetype, be sure to update the Macro for this analytic. Recommend running it daily, or weekly, depending on threat model.
known_false_positives: No false positives here, only bootloaders. Filter as needed or create a lookup as a baseline.
references:
    - https://gist.github.com/MHaggis/26518cd2844b0e03de6126660bb45707
    - https://www.microsoft.com/en-us/security/blog/2023/04/11/guidance-for-investigating-attacks-using-cve-2022-21894-the-blacklotus-campaign/
analytic_story:
    - BlackLotus Campaign
    - Windows BootKits
asset_type: Endpoint
mitre_attack_id:
    - T1542.001
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

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