DNS-over-HTTPS Enabled via Registry

Elastic Stack Serverless Security

Identifies when a user enables DNS-over-HTTPS. This can be used to hide internet activity or the process of exfiltrating data. With this enabled, an organization will lose visibility into data such as query type, response, and originating IP, which are used to determine bad actors.

Rule type: eql

Rule indices:

winlogbeat-*
logs-endpoint.events.*
logs-windows.*

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

Elastic
Host
Windows
Threat Detection
Defense Evasion

Version: 3

Rule authors:

Austin Songer

Rule license: Elastic License v2

Investigation guide

Config

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define event.ingested and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate event.ingested to @timestamp for this rule to work.

Rule query

		registry where event.type in ("creation", "change") and
  (registry.path : "*\\SOFTWARE\\Policies\\Microsoft\\Edge\\BuiltInDnsClientEnabled" and
  registry.data.strings : "1") or
  (registry.path : "*\\SOFTWARE\\Google\\Chrome\\DnsOverHttpsMode" and
  registry.data.strings : "secure") or
  (registry.path : "*\\SOFTWARE\\Policies\\Mozilla\\Firefox\\DNSOverHTTPS" and
  registry.data.strings : "1")

	

Framework: MITRE ATT&CKTM

Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Impair Defenses
- ID: T1562
- Reference URL: https://attack.mitre.org/techniques/T1562/