LoFP / 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.

Techniques

• T1036
• T1036.003
• T1127
• T1127.001

Sample rules

Suspicious msbuild path

• source: splunk
• technicques:
  • T1036
  • T1127
  • T1036.003
  • T1127.001

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.

Detection logic

| 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 `process_msbuild` AND (Processes.process_path!=*\\framework*\\v*\\*) by Processes.dest Processes.original_file_name Processes.parent_process Processes.user 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)`
| `suspicious_msbuild_path_filter`