Microsoft Build Engine Started an Unusual Process
editMicrosoft Build Engine Started an Unusual Process
editAn instance of MSBuild, the Microsoft Build Engine, started a PowerShell script or the Visual C# Command Line Compiler. This technique is sometimes used to deploy a malicious payload using the Build Engine.
Rule type: eql
Rule indices:
- winlogbeat-*
- logs-endpoint.events.*
- logs-windows.*
- endgame-*
Severity: low
Risk score: 21
Runs every: 5 minutes
Searches indices from: now-9m (Date Math format, see also Additional look-back time
)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Defense Evasion
- Elastic Endgame
Version: 102 (version history)
Added (Elastic Stack release): 7.7.0
Last modified (Elastic Stack release): 8.6.0
Rule authors: Elastic
Rule license: Elastic License v2
Potential false positives
editThe Build Engine is commonly used by Windows developers but use by non-engineers is unusual. If a build system triggers this rule it can be exempted by process, user or host name.
Investigation guide
editRule query
editprocess where event.type == "start" and process.parent.name : "MSBuild.exe" and process.name : ("csc.exe", "iexplore.exe", "powershell.exe")
Threat mapping
editFramework: MITRE ATT&CKTM
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
-
Technique:
- Name: Obfuscated Files or Information
- ID: T1027
- Reference URL: https://attack.mitre.org/techniques/T1027/
Rule version history
edit- Version 102 (8.6.0 release)
-
- Formatting only
- Version 101 (8.5.0 release)
-
-
Updated query, changed from:
process where event.type in ("start", "process_started") and process.parent.name : "MSBuild.exe" and process.name : ("csc.exe", "iexplore.exe", "powershell.exe")
-
- Version 11 (8.4.0 release)
-
- Formatting only
- Version 9 (8.2.0 release)
-
- Formatting only
- Version 8 (7.13.0 release)
-
-
Updated query, changed from:
event.category:process and event.type:(start or process_started) and process.parent.name:MSBuild.exe and process.name:(csc.exe or iexplore.exe or powershell.exe)
-
- Version 7 (7.12.0 release)
-
- Formatting only
- Version 6 (7.11.2 release)
-
- Formatting only
- Version 5 (7.11.0 release)
-
- Formatting only
- Version 4 (7.10.0 release)
-
- Formatting only
- Version 3 (7.9.1 release)
-
- Formatting only
- Version 2 (7.9.0 release)
-
-
Updated query, changed from:
process.parent.name:MSBuild.exe and process.name:(csc.exe or iexplore.exe or powershell.exe)
-