---
title: "Suspicious MSBuild Spawn"
excerpt: "Trusted Developer Utilities Proxy Execution, MSBuild"
categories:
  - Endpoint
last_modified_at: 2021-01-12
toc: true
toc_label: ""
tags:
  - Trusted Developer Utilities Proxy Execution
  - Defense Evasion
  - MSBuild
  - Defense Evasion
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  - Endpoint
---



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#### 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.

- **Type**: [TTP](https://github.com/splunk/security_content/wiki/Detection-Analytic-Types)
- **Product**: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- **Datamodel**: [Endpoint](https://docs.splunk.com/Documentation/CIM/latest/User/Endpoint)
- **Last Updated**: 2021-01-12
- **Author**: Michael Haag, Splunk
- **ID**: a115fba6-5514-11eb-ae93-0242ac130002


#### [ATT&CK](https://attack.mitre.org/)

| ID             | Technique        |  Tactic             |
| -------------- | ---------------- |-------------------- |
| [T1127](https://attack.mitre.org/techniques/T1127/) | Trusted Developer Utilities Proxy Execution | Defense Evasion |

| [T1127.001](https://attack.mitre.org/techniques/T1127/001/) | MSBuild | Defense Evasion |

#### 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.dest Processes.parent_process Processes.original_file_name Processes.user 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `suspicious_msbuild_spawn_filter`
```

#### Macros
The SPL above uses the following Macros:
* [process_msbuild](https://github.com/splunk/security_content/blob/develop/macros/process_msbuild.yml)
* [security_content_ctime](https://github.com/splunk/security_content/blob/develop/macros/security_content_ctime.yml)
* [security_content_summariesonly](https://github.com/splunk/security_content/blob/develop/macros/security_content_summariesonly.yml)

Note that `suspicious_msbuild_spawn_filter` is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

#### Required field
* _time
* Processes.dest
* Processes.user
* Processes.parent_process_name
* Processes.parent_process
* Processes.original_file_name
* Processes.process_name
* Processes.process
* Processes.process_id
* Processes.parent_process_path
* Processes.process_path
* Processes.parent_process_id


#### 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.

#### Associated Analytic story
* [Trusted Developer Utilities Proxy Execution MSBuild](/stories/trusted_developer_utilities_proxy_execution_msbuild)


#### Kill Chain Phase
* Exploitation



#### RBA

| Risk Score  | Impact      | Confidence   | Message      |
| ----------- | ----------- |--------------|--------------|
| 42.0 | 70 | 60 | Suspicious msbuild.exe process executed on $dest$ by $user$ |


Note that risk score is calculated base on the following formula: `(Impact * Confidence)/100`



#### Reference

* [https://lolbas-project.github.io/lolbas/Binaries/Msbuild/](https://lolbas-project.github.io/lolbas/Binaries/Msbuild/)
* [https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1127.001/T1127.001.md](https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1127.001/T1127.001.md)



#### Test Dataset
Replay any dataset to Splunk Enterprise by using our [`replay.py`](https://github.com/splunk/attack_data#using-replaypy) tool or the [UI](https://github.com/splunk/attack_data#using-ui).
Alternatively you can replay a dataset into a [Splunk Attack Range](https://github.com/splunk/attack_range#replay-dumps-into-attack-range-splunk-server)

* [https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1127.001/windows-sysmon.log](https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1127.001/windows-sysmon.log)



[*source*](https://github.com/splunk/security_content/tree/develop/detections/endpoint/suspicious_msbuild_spawn.yml) \| *version*: **2**