name: Suspicious msbuild path
id: f5198224-551c-11eb-ae93-0242ac130002
version: 3
date: '2022-03-08'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic identifies msbuild.exe executing from a non-standard
  path. Msbuild.exe is natively found in C:\Windows\Microsoft.NET\Framework\v4.0.30319
  and C:\Windows\Microsoft.NET\Framework64\v4.0.30319. Instances of Visual Studio
  will run a copy of msbuild.exe. A moved instance of MSBuild is suspicious, however
  there are instances of build applications that will move or use a copy of MSBuild.
data_source:
- Sysmon Event ID 1
search:
  selection1:
    OriginalFileName: MSBuild.exe
  selection2:
    Image|endswith: msbuild.exe
  selection3:
    Processes.process_path: '*\\framework*\\v*\\*'
  condition: (selection1 or 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: Some legitimate applications may use a moved copy of msbuild.exe,
  triggering a false positive. Baselining of MSBuild.exe usage is recommended to better
  understand it's path usage. Visual Studio runs an instance out of a path that will
  need to be filtered on.
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
  - Cobalt Strike
  - Masquerading - Rename System Utilities
  - Living Off The Land
  asset_type: Endpoint
  confidence: 70
  impact: 70
  message: Msbuild.exe ran from an uncommon path on $dest$ execyted by $user$
  mitre_attack_id:
  - T1036
  - T1127
  - T1036.003
  - 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: 49
  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