Potential Application Whitelisting Bypass via Dnx.EXE — Sigma Rule

Rule metadata and linked tags

Author: Beyu Denis, oscd.community. Source status: test; severity: medium. Source dates: 2019-10-26 / 2024-04-24.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 5dbe6e226a98a8ecf194ef25b934dec3f859539cfbb87d56c0a12a86196aa19b

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Potential Application Whitelisting Bypass via Dnx.EXE
id: 81ebd28b-9607-4478-bf06-974ed9d53ed7
status: test
description: |
    Detects the execution of Dnx.EXE. The Dnx utility allows for the execution of C# code.
    Attackers might abuse this in order to bypass application whitelisting.
references:
    - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Csi/
    - https://enigma0x3.net/2016/11/17/bypassing-application-whitelisting-by-using-dnx-exe/
author: Beyu Denis, oscd.community
date: 2019-10-26
modified: 2024-04-24
tags:
    - attack.stealth
    - attack.t1218
    - attack.t1027.004
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\dnx.exe'
    condition: selection
falsepositives:
    - Legitimate use of dnx.exe by legitimate user
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate use of dnx.exe by legitimate user

Source references

• https://lolbas-project.github.io/lolbas/OtherMSBinaries/Csi/
• https://enigma0x3.net/2016/11/17/bypassing-application-whitelisting-by-using-dnx-exe/