Convert indexed Sigma rules into analyst-ready detections.

title: Network Connection Initiated To AzureWebsites.NET By Non-Browser Process
id: 5c80b618-0dbb-46e6-acbb-03d90bcb6d83
related:
    - id: e043f529-8514-4205-8ab0-7f7d2927b400
      type: derived
status: test
description: |
    Detects an initiated network connection 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
modified: 2024-07-16
tags:
    - attack.command-and-control
    - attack.t1102
    - attack.t1102.001
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        Initiated: 'true'
        DestinationHostname|endswith: 'azurewebsites.net'
    # Note: Add/Remove browsers/applications that you don't use or those that have custom install locations
    # Note: To avoid complex conditions the filters for some apps are generic by name only. A custom tuning is recommended for best results
    filter_main_chrome:
        Image:
            - 'C:\Program Files\Google\Chrome\Application\chrome.exe'
            - 'C:\Program Files (x86)\Google\Chrome\Application\chrome.exe'
    filter_main_chrome_appdata:
        Image|startswith: 'C:\Users\'
        Image|endswith: '\AppData\Local\Google\Chrome\Application\chrome.exe'
    filter_main_firefox:
        Image:
            - 'C:\Program Files\Mozilla Firefox\firefox.exe'
            - 'C:\Program Files (x86)\Mozilla Firefox\firefox.exe'
    filter_main_firefox_appdata:
        Image|startswith: 'C:\Users\'
        Image|endswith: '\AppData\Local\Mozilla Firefox\firefox.exe'
    filter_main_ie:
        Image:
            - 'C:\Program Files (x86)\Internet Explorer\iexplore.exe'
            - 'C:\Program Files\Internet Explorer\iexplore.exe'
    filter_main_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_main_edge_2:
        Image|startswith:
            - 'C:\Program Files (x86)\Microsoft\EdgeCore\'
            - 'C:\Program Files\Microsoft\EdgeCore\'
        Image|endswith:
            - '\msedge.exe'
            - '\msedgewebview2.exe'
    filter_main_safari:
        Image|contains:
            - 'C:\Program Files (x86)\Safari\'
            - 'C:\Program Files\Safari\'
        Image|endswith: '\safari.exe'
    filter_main_defender:
        Image|contains:
            - 'C:\Program Files\Windows Defender Advanced Threat Protection\'
            - 'C:\Program Files\Windows Defender\'
            - 'C:\ProgramData\Microsoft\Windows Defender\Platform\'
        Image|endswith:
            - '\MsMpEng.exe' # Microsoft Defender executable
            - '\MsSense.exe' # Windows Defender Advanced Threat Protection Service Executable
    filter_main_prtg:
        # Paessler's PRTG Network Monitor
        Image|endswith:
            - 'C:\Program Files (x86)\PRTG Network Monitor\PRTG Probe.exe'
            - 'C:\Program Files\PRTG Network Monitor\PRTG Probe.exe'
    filter_main_brave:
        Image|startswith: 'C:\Program Files\BraveSoftware\'
        Image|endswith: '\brave.exe'
    filter_main_maxthon:
        Image|contains: '\AppData\Local\Maxthon\'
        Image|endswith: '\maxthon.exe'
    filter_main_opera:
        Image|contains: '\AppData\Local\Programs\Opera\'
        Image|endswith: '\opera.exe'
    filter_main_seamonkey:
        Image|startswith:
            - 'C:\Program Files\SeaMonkey\'
            - 'C:\Program Files (x86)\SeaMonkey\'
        Image|endswith: '\seamonkey.exe'
    filter_main_vivaldi:
        Image|contains: '\AppData\Local\Vivaldi\'
        Image|endswith: '\vivaldi.exe'
    filter_main_whale:
        Image|startswith:
            - 'C:\Program Files\Naver\Naver Whale\'
            - 'C:\Program Files (x86)\Naver\Naver Whale\'
        Image|endswith: '\whale.exe'
    # Note: The TOR browser shouldn't be something you allow in your corporate network.
    # filter_main_tor:
    #     Image|contains: '\Tor Browser\'
    filter_main_whaterfox:
        Image|startswith:
            - 'C:\Program Files\Waterfox\'
            - 'C:\Program Files (x86)\Waterfox\'
        Image|endswith: '\Waterfox.exe'
    filter_main_slimbrowser:
        Image|startswith:
            - 'C:\Program Files\SlimBrowser\'
            - 'C:\Program Files (x86)\SlimBrowser\'
        Image|endswith: '\slimbrowser.exe'
    filter_main_flock:
        Image|contains: '\AppData\Local\Flock\'
        Image|endswith: '\Flock.exe'
    filter_main_phoebe:
        Image|contains: '\AppData\Local\Phoebe\'
        Image|endswith: '\Phoebe.exe'
    filter_main_falkon:
        Image|startswith:
            - 'C:\Program Files\Falkon\'
            - 'C:\Program Files (x86)\Falkon\'
        Image|endswith: '\falkon.exe'
    filter_main_qtweb:
        Image|startswith:
            - 'C:\Program Files (x86)\QtWeb\'
            - 'C:\Program Files\QtWeb\'
        Image|endswith: '\QtWeb.exe'
    filter_main_avant:
        Image|startswith:
            - 'C:\Program Files (x86)\Avant Browser\'
            - 'C:\Program Files\Avant Browser\'
        Image|endswith: '\avant.exe'
    filter_main_discord:
        Image|contains: '\AppData\Local\Discord\'
        Image|endswith: '\Discord.exe'
    filter_main_null:
        Image: null
    filter_main_empty:
        Image: ''
    # filter_optional_qlik:
    #     Image|endswith: '\Engine.exe' # Process from qlik.com app
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: medium