Sigma Rule Library

DNS Query To AzureWebsites.NET By Non-Browser Process

Detects a DNS query by a non browser process on the system to "azurewebsites.net". The latter was often used by threat actors as a malware hosting and exfiltration site.

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Detection logic

selection

QueryName|endswith: azurewebsites.net

filter_optional_chrome

Image:
  - C:\Program Files\Google\Chrome\Application\chrome.exe
  - C:\Program Files (x86)\Google\Chrome\Application\chrome.exe

filter_optional_firefox

Image:
  - C:\Program Files\Mozilla Firefox\firefox.exe
  - C:\Program Files (x86)\Mozilla Firefox\firefox.exe

filter_optional_ie

Image:
  - C:\Program Files (x86)\Internet Explorer\iexplore.exe
  - C:\Program Files\Internet Explorer\iexplore.exe

filter_optional_edge_1

- Image|startswith: C:\Program Files (x86)\Microsoft\EdgeWebView\Application\
- Image|endswith: \WindowsApps\MicrosoftEdge.exe
- Image:
    - C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe
    - C:\Program Files\Microsoft\Edge\Application\msedge.exe

filter_optional_edge_2

Image|startswith:
  - C:\Program Files (x86)\Microsoft\EdgeCore\
  - C:\Program Files\Microsoft\EdgeCore\
Image|endswith:
  - \msedge.exe
  - \msedgewebview2.exe

filter_optional_safari

Image|endswith: \safari.exe

filter_optional_defender

Image|endswith:
  - \MsMpEng.exe
  - \MsSense.exe

filter_optional_brave

Image|endswith: \brave.exe
Image|startswith: C:\Program Files\BraveSoftware\

filter_optional_maxthon

Image|contains: \AppData\Local\Maxthon\
Image|endswith: \maxthon.exe

filter_optional_opera

Image|contains: \AppData\Local\Programs\Opera\
Image|endswith: \opera.exe

filter_optional_seamonkey

Image|startswith:
  - C:\Program Files\SeaMonkey\
  - C:\Program Files (x86)\SeaMonkey\
Image|endswith: \seamonkey.exe

filter_optional_vivaldi

Image|contains: \AppData\Local\Vivaldi\
Image|endswith: \vivaldi.exe

filter_optional_whale

Image|startswith:
  - C:\Program Files\Naver\Naver Whale\
  - C:\Program Files (x86)\Naver\Naver Whale\
Image|endswith: \whale.exe

filter_optional_tor

Image|contains: \Tor Browser\

filter_optional_whaterfox

Image|startswith:
  - C:\Program Files\Waterfox\
  - C:\Program Files (x86)\Waterfox\
Image|endswith: \Waterfox.exe

filter_optional_midori

Image|contains: \AppData\Local\Programs\midori-ng\
Image|endswith: \Midori Next Generation.exe

filter_optional_slimbrowser

Image|startswith:
  - C:\Program Files\SlimBrowser\
  - C:\Program Files (x86)\SlimBrowser\
Image|endswith: \slimbrowser.exe

filter_optional_flock

Image|contains: \AppData\Local\Flock\
Image|endswith: \Flock.exe

filter_optional_phoebe

Image|contains: \AppData\Local\Phoebe\
Image|endswith: \Phoebe.exe

filter_optional_falkon

Image|startswith:
  - C:\Program Files\Falkon\
  - C:\Program Files (x86)\Falkon\
Image|endswith: \falkon.exe

filter_optional_avant

Image|startswith:
  - C:\Program Files (x86)\Avant Browser\
  - C:\Program Files\Avant Browser\
Image|endswith: \avant.exe

Condition

selection and not 1 of filter_optional_*

Raw YAML

title: DNS Query To AzureWebsites.NET By Non-Browser Process
id: e043f529-8514-4205-8ab0-7f7d2927b400
related:
    - id: 5c80b618-0dbb-46e6-acbb-03d90bcb6d83
      type: derived
status: test
description: |
    Detects a DNS query by a non browser process on the system to "azurewebsites.net". The latter was often used by threat actors as a malware hosting and exfiltration site.
references:
    - https://www.sentinelone.com/labs/wip26-espionage-threat-actors-abuse-cloud-infrastructure-in-targeted-telco-attacks/
    - https://symantec-enterprise-blogs.security.com/threat-intelligence/harvester-new-apt-attacks-asia
    - https://www.ptsecurity.com/ww-en/analytics/pt-esc-threat-intelligence/higaisa-or-winnti-apt-41-backdoors-old-and-new/
    - https://intezer.com/blog/research/how-we-escaped-docker-in-azure-functions/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2024-06-24
tags:
    - attack.command-and-control
    - attack.t1219.002
logsource:
    product: windows
    category: dns_query
detection:
    selection:
        QueryName|endswith: 'azurewebsites.net'
    filter_optional_chrome:
        Image:
            - 'C:\Program Files\Google\Chrome\Application\chrome.exe'
            - 'C:\Program Files (x86)\Google\Chrome\Application\chrome.exe'
    filter_optional_firefox:
        Image:
            - 'C:\Program Files\Mozilla Firefox\firefox.exe'
            - 'C:\Program Files (x86)\Mozilla Firefox\firefox.exe'
    filter_optional_ie:
        Image:
            - 'C:\Program Files (x86)\Internet Explorer\iexplore.exe'
            - 'C:\Program Files\Internet Explorer\iexplore.exe'
    filter_optional_edge_1:
        - Image|startswith: 'C:\Program Files (x86)\Microsoft\EdgeWebView\Application\'
        - Image|endswith: '\WindowsApps\MicrosoftEdge.exe'
        - Image:
              - 'C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe'
              - 'C:\Program Files\Microsoft\Edge\Application\msedge.exe'
    filter_optional_edge_2:
        Image|startswith:
            - 'C:\Program Files (x86)\Microsoft\EdgeCore\'
            - 'C:\Program Files\Microsoft\EdgeCore\'
        Image|endswith:
            - '\msedge.exe'
            - '\msedgewebview2.exe'
    filter_optional_safari:
        Image|endswith: '\safari.exe'
    filter_optional_defender:
        Image|endswith:
            - '\MsMpEng.exe' # Microsoft Defender executable
            - '\MsSense.exe' # Windows Defender Advanced Threat Protection Service Executable
    filter_optional_brave:
        Image|endswith: '\brave.exe'
        Image|startswith: 'C:\Program Files\BraveSoftware\'
    filter_optional_maxthon:
        Image|contains: '\AppData\Local\Maxthon\'
        Image|endswith: '\maxthon.exe'
    filter_optional_opera:
        Image|contains: '\AppData\Local\Programs\Opera\'
        Image|endswith: '\opera.exe'
    filter_optional_seamonkey:
        Image|startswith:
            - 'C:\Program Files\SeaMonkey\'
            - 'C:\Program Files (x86)\SeaMonkey\'
        Image|endswith: '\seamonkey.exe'
    filter_optional_vivaldi:
        Image|contains: '\AppData\Local\Vivaldi\'
        Image|endswith: '\vivaldi.exe'
    filter_optional_whale:
        Image|startswith:
            - 'C:\Program Files\Naver\Naver Whale\'
            - 'C:\Program Files (x86)\Naver\Naver Whale\'
        Image|endswith: '\whale.exe'
    filter_optional_tor:
        Image|contains: '\Tor Browser\'
    filter_optional_whaterfox:
        Image|startswith:
            - 'C:\Program Files\Waterfox\'
            - 'C:\Program Files (x86)\Waterfox\'
        Image|endswith: '\Waterfox.exe'
    filter_optional_midori:
        Image|contains: '\AppData\Local\Programs\midori-ng\'
        Image|endswith: '\Midori Next Generation.exe'
    filter_optional_slimbrowser:
        Image|startswith:
            - 'C:\Program Files\SlimBrowser\'
            - 'C:\Program Files (x86)\SlimBrowser\'
        Image|endswith: '\slimbrowser.exe'
    filter_optional_flock:
        Image|contains: '\AppData\Local\Flock\'
        Image|endswith: '\Flock.exe'
    filter_optional_phoebe:
        Image|contains: '\AppData\Local\Phoebe\'
        Image|endswith: '\Phoebe.exe'
    filter_optional_falkon:
        Image|startswith:
            - 'C:\Program Files\Falkon\'
            - 'C:\Program Files (x86)\Falkon\'
        Image|endswith: '\falkon.exe'
    filter_optional_avant:
        Image|startswith:
            - 'C:\Program Files (x86)\Avant Browser\'
            - 'C:\Program Files\Avant Browser\'
        Image|endswith: '\avant.exe'
    condition: selection and not 1 of filter_optional_*
falsepositives:
    - Likely with other browser software. Apply additional filters for any other browsers you might use.
level: medium

False positives

  • Likely with other browser software. Apply additional filters for any other browsers you might use.

References

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