name: Suspicious MSBuild Spawn
id: a115fba6-5514-11eb-ae93-0242ac130002
version: 2
date: '2021-01-12'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic identifies wmiprvse.exe spawning msbuild.exe.
  This behavior is indicative of a COM object being utilized to spawn msbuild from
  wmiprvse.exe. It is common for MSBuild.exe to be spawned from devenv.exe while using
  Visual Studio. In this instance, there will be command line arguments and file paths.
  In a malicious instance, MSBuild.exe will spawn from non-standard processes and
  have no command line arguments. For example, MSBuild.exe spawning from explorer.exe,
  powershell.exe is far less common and should be investigated.
data_source:
- Sysmon Event ID 1
search:
  selection1:
    ParentImage: wmiprvse.exe
  selection2:
    OriginalFileName: MSBuild.exe
  selection3:
    Image|endswith: msbuild.exe
  condition: selection1 and selection2 and selection3
how_to_implement: To successfully implement this search you need to be ingesting information
  on process that include the name of the process responsible for the changes from
  your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition,
  confirm the latest CIM App 4.20 or higher is installed and the latest TA for the
  endpoint product.
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
tags:
  analytic_story:
  - Trusted Developer Utilities Proxy Execution MSBuild
  - Living Off The Land
  asset_type: Endpoint
  confidence: 60
  impact: 70
  message: Suspicious msbuild.exe process executed on $dest$ by $user$
  mitre_attack_id:
  - T1127
  - T1127.001
  observable:
  - name: dest
    type: Endpoint
    role:
    - Victim
  - name: User
    type: User
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  risk_score: 42
  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
    update_timestamp: true