Application Whitelisting bypass via dnx.exe

Execute C# code located in the consoleapp folder

Rule Content

- title: Application Whitelisting bypass via dnx.exe
  id: 81ebd28b-9607-4478-bf06-974ed9d53ed7
  status: experimental
  description: Execute C# code located in the consoleapp folder
  references:
  - https://github.com/LOLBAS-Project/LOLBAS/blob/master/yml/OtherMSBinaries/Csi.yml
  - https://enigma0x3.net/2016/11/17/bypassing-application-whitelisting-by-using-dnx-exe/
  author: Beyu Denis, oscd.community
  date: 2019/10/26
  modified: 2019/11/04
  tags:
  - attack.defense_evasion
  - attack.execution
  - attack.t1218
  level: medium
  logsource:
    category: process_creation
    product: windows
    service: null
  detection:
    selection:
      Image|endswith: \dnx.exe
    condition: selection
  falsepositives:
  - Legitimate use of dnx.exe by legitimate user

Querying Elasticsearch

Import Libraries



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from elasticsearch import Elasticsearch
from elasticsearch_dsl import Search
import pandas as pd

Initialize Elasticsearch client



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es = Elasticsearch(['http://helk-elasticsearch:9200'])
searchContext = Search(using=es, index='logs-*', doc_type='doc')

Run Elasticsearch Query



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s = searchContext.query('query_string', query='process_path.keyword:*\\dnx.exe')
response = s.execute()
if response.success():
    df = pd.DataFrame((d.to_dict() for d in s.scan()))

Show Results



In [ ]:

    
df.head()