Suspicious MSBuild Spawn

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

The following analytic identifies instances where wmiprvse.exe spawns msbuild.exe, which is unusual and indicative of potential misuse of a COM object. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process relationships and command-line executions. This activity is significant because msbuild.exe is typically spawned by devenv.exe during legitimate Visual Studio use, not by wmiprvse.exe. If confirmed malicious, this behavior could indicate an attacker executing arbitrary code or scripts, potentially leading to system compromise or further malicious activities.

name: Suspicious MSBuild Spawn
id: a115fba6-5514-11eb-ae93-0242ac130002
version: 14
creation_date: '2021-01-15'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic identifies instances where wmiprvse.exe spawns msbuild.exe, which is unusual and indicative of potential misuse of a COM object. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process relationships and command-line executions. This activity is significant because msbuild.exe is typically spawned by devenv.exe during legitimate Visual Studio use, not by wmiprvse.exe. If confirmed malicious, this behavior could indicate an attacker executing arbitrary code or scripts, potentially leading to system compromise or further malicious activities.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |-
    | tstats `security_content_summariesonly` count values(Processes.process_name) as process_name values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
      WHERE Processes.parent_process_name=wmiprvse.exe
        AND
        `process_msbuild`
      BY Processes.action Processes.dest Processes.original_file_name
         Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
         Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
         Processes.process Processes.process_exec Processes.process_guid
         Processes.process_hash Processes.process_id Processes.process_integrity_level
         Processes.process_name Processes.process_path Processes.user
         Processes.user_id Processes.vendor_product
    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `suspicious_msbuild_spawn_filter`
how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives: Although unlikely, some legitimate applications may exhibit this behavior, triggering a false positive.
references:
    - https://lolbas-project.github.io/lolbas/Binaries/Msbuild/
    - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1127.001/T1127.001.md
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: Suspicious msbuild.exe process executed on $dest$ by $user$
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: Suspicious msbuild.exe process executed on $dest$ by $user$
analytic_story:
    - Trusted Developer Utilities Proxy Execution MSBuild
    - Living Off The Land
    - Storm-2460 CLFS Zero Day Exploitation
asset_type: Endpoint
mitre_attack_id:
    - T1127.001
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/T1127.001/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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159e49f4-9281-469c-8888-b0f260e3abd3

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