Bitsadmin to Uncommon TLD

Detects Bitsadmin connections to domains with uncommon TLDs - https://twitter.com/jhencinski/status/1102695118455349248 - https://isc.sans.edu/forums/diary/Investigating+Microsoft+BITS+Activity/23281/

Rule Content

- title: Bitsadmin to Uncommon TLD
  id: 9eb68894-7476-4cd6-8752-23b51f5883a7
  status: experimental
  description: Detects Bitsadmin connections to domains with uncommon TLDs - https://twitter.com/jhencinski/status/1102695118455349248
    - https://isc.sans.edu/forums/diary/Investigating+Microsoft+BITS+Activity/23281/
  author: Florian Roth
  date: 2019/03/07
  logsource:
    category: proxy
    product: null
    service: null
  detection:
    selection:
      c-useragent:
      - Microsoft BITS/*
    falsepositives:
      r-dns:
      - '*.com'
      - '*.net'
      - '*.org'
    condition: selection and not falsepositives
  fields:
  - ClientIP
  - c-uri
  - c-useragent
  falsepositives:
  - Rare programs that use Bitsadmin and update from regional TLDs e.g. .uk or .ca
  level: high

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='(c-useragent.keyword:(Microsoft\ BITS\/*) AND (NOT (r-dns.keyword:(*.com OR *.net OR *.org))))')
response = s.execute()
if response.success():
    df = pd.DataFrame((d.to_dict() for d in s.scan()))

Show Results



In [ ]:

    
df.head()