Windows: Dotnet.exe executes arbitrary DLL or csproj files

Alerts when dotnet.exe runs with .csproj or .dll arguments that may indicate loading or execution of untrusted .NET code.

FreeReviewedSigma · Medium · v2

Product: windows
Category: process_creation
Author: Beyu Denis, oscd.community (SigmaHQ), DRL 1.1
Published: 2020-10-18
Updated: 2026-07-31

Analysis Detection

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218System Binary Proxy Execution
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags process executions where dotnet.exe is launched with command-line arguments ending in .csproj or .dll, indicating potential execution of attacker-controlled build or library artifacts. Such behavior matters because it can enable stealthy code execution paths that blend into normal .NET tooling. Telemetry relies on Windows process creation events, including the process image (dotnet.exe) and the full command line.

Reporting behind it

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Windows: Dotnet.exe executes arbitrary DLL or csproj files

Pivot detection · T1218 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-arbitrary-dll-or-csproj-code-execution-via-dotnet-exe-d80d5c81

title: "Windows: Dotnet.exe executes arbitrary DLL or csproj files"
id: 61ac7ee2-0f8c-4f29-a6b5-e66e34236bfc
status: test
description: This rule flags process executions where dotnet.exe is launched with command-line arguments ending in .csproj or .dll, indicating potential execution of attacker-controlled build or library artifacts. Such behavior matters because it can enable stealthy code execution paths that blend into normal .NET tooling. Telemetry relies on Windows process creation events, including the process image (dotnet.exe) and the full command line.
references:
  - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Dotnet/
  - https://twitter.com/_felamos/status/1204705548668555264
  - https://bohops.com/2019/08/19/dotnet-core-a-vector-for-awl-bypass-defense-evasion/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_dotnet_arbitrary_dll_csproj_execution.yml
author: Beyu Denis, oscd.community, Huntrule Team
date: 2020-10-18
modified: 2025-10-08
tags:
  - attack.stealth
  - attack.t1218
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith: \dotnet.exe
    - OriginalFileName: .NET Host
  selection_cli:
    CommandLine|endswith:
      - .csproj
      - .csproj"
      - .dll
      - .dll"
      - .csproj'
      - .dll'
  filter_optional_notepadplus_plus:
    ParentImage:
      - C:\Program Files (x86)\Notepad++\notepad++.exe
      - C:\Program Files\Notepad++\notepad++.exe
    CommandLine|contains|all:
      - C:\ProgramData\CSScriptNpp\
      - "-cscs_path:"
      - \cs-script\cscs.dll
  condition: all of selection_* and not 1 of filter_optional_*
falsepositives:
  - Legitimate administrator usage
level: medium
license: DRL-1.1
related:
  - id: d80d5c81-04ba-45b4-84e4-92eba40e0ad3
    type: derived

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