Windows DNS queries for public IP lookup API domains by non-browser processes

Flags suspicious DNS lookups to IP-check API domains on Windows when they come from non-browser executables.

FreeUnreviewedSigmamediumv1
title: Windows DNS queries for public IP lookup API domains by non-browser processes
id: aaa21c8d-84cf-4d9f-b2b3-1dea6dbc1894
status: test
description: This rule identifies Windows DNS query activity for well-known IP lookup service domains (including api.ipify.org and other similar services) when the originating process is not one of several common web browsers. Such DNS lookups can be used by attackers or scripts to determine external IP address during reconnaissance or automated behavior. Telemetry required includes DNS query logs containing QueryName and process image path information for filtering browser-originating queries.
references:
  - https://www.binarydefense.com/analysis-of-hancitor-when-boring-begets-beacon
  - https://twitter.com/neonprimetime/status/1436376497980428318
  - https://www.trendmicro.com/en_us/research/23/e/managed-xdr-investigation-of-ducktail-in-trend-micro-vision-one.html
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/dns_query/dns_query_win_susp_external_ip_lookup.yml
author: Brandon George (blog post), Thomas Patzke, Huntrule Team
date: 2021-07-08
modified: 2024-03-22
tags:
  - attack.reconnaissance
  - attack.t1590
logsource:
  product: windows
  category: dns_query
detection:
  selection:
    - QueryName:
        - www.ip.cn
        - l2.io
    - QueryName|contains:
        - api.2ip.ua
        - api.bigdatacloud.net
        - api.ipify.org
        - bot.whatismyipaddress.com
        - canireachthe.net
        - checkip.amazonaws.com
        - checkip.dyndns.org
        - curlmyip.com
        - db-ip.com
        - edns.ip-api.com
        - eth0.me
        - freegeoip.app
        - geoipy.com
        - getip.pro
        - icanhazip.com
        - ident.me
        - ifconfig.io
        - ifconfig.me
        - ip-api.com
        - ip.360.cn
        - ip.anysrc.net
        - ip.taobao.com
        - ip.tyk.nu
        - ipaddressworld.com
        - ipapi.co
        - ipconfig.io
        - ipecho.net
        - ipinfo.io
        - ipip.net
        - ipof.in
        - ipv4.icanhazip.com
        - ipv4bot.whatismyipaddress.com
        - ipv6-test.com
        - ipwho.is
        - jsonip.com
        - myexternalip.com
        - seeip.org
        - wgetip.com
        - whatismyip.akamai.com
        - whois.pconline.com.cn
        - wtfismyip.com
  filter_optional_brave:
    Image|endswith: \brave.exe
  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_maxthon:
    Image|endswith: \maxthon.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_opera:
    Image|endswith: \opera.exe
  filter_optional_safari:
    Image|endswith: \safari.exe
  filter_optional_seamonkey:
    Image|endswith: \seamonkey.exe
  filter_optional_vivaldi:
    Image|endswith: \vivaldi.exe
  filter_optional_whale:
    Image|endswith: \whale.exe
  condition: selection and not 1 of filter_optional_*
falsepositives:
  - Legitimate usage of IP lookup services such as ipify API
level: medium
license: DRL-1.1
related:
  - id: ec82e2a5-81ea-4211-a1f8-37a0286df2c2
    type: derived

What it detects

This rule identifies Windows DNS query activity for well-known IP lookup service domains (including api.ipify.org and other similar services) when the originating process is not one of several common web browsers. Such DNS lookups can be used by attackers or scripts to determine external IP address during reconnaissance or automated behavior. Telemetry required includes DNS query logs containing QueryName and process image path information for filtering browser-originating queries.

Known false positives

  • Legitimate usage of IP lookup services such as ipify API

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.