DNS-over-HTTPS Enabled by Registry

Status: test
Severity: medium
Log source: product windows, category registry_set
Author: Austin Songer
Source: github.com/SigmaHQ/sigma

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

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1112` Modify Registry
Stealth	`T1140` Deobfuscate/Decode Files or Information
Defense Impairment	`T1112` Modify Registry

Event coverage

Provider	Event	Title
Sysmon	Event ID 13	RegistryEvent (Value Set)

Rule body yaml

title: DNS-over-HTTPS Enabled by Registry
id: 04b45a8a-d11d-49e4-9acc-4a1b524407a5
status: test
description: |
    Detects when a user enables DNS-over-HTTPS.
    This can be used to hide internet activity or be used to hide the process of exfiltrating data.
    With this enabled organization will lose visibility into data such as query type, response and originating IP that are used to determine bad actors.
references:
    - https://www.tenforums.com/tutorials/151318-how-enable-disable-dns-over-https-doh-microsoft-edge.html
    - https://github.com/elastic/detection-rules/issues/1371
    - https://chromeenterprise.google/policies/?policy=DnsOverHttpsMode
    - https://admx.help/HKLM/Software/Policies/Mozilla/Firefox/DNSOverHTTPS
author: Austin Songer
date: 2021-07-22
modified: 2023-08-17
tags:
    - attack.persistence
    - attack.stealth
    - attack.defense-impairment
    - attack.t1140
    - attack.t1112
logsource:
    product: windows
    category: registry_set
detection:
    selection_edge:
        TargetObject|endswith: '\SOFTWARE\Policies\Microsoft\Edge\BuiltInDnsClientEnabled'
        Details: DWORD (0x00000001)
    selection_chrome:
        TargetObject|endswith: '\SOFTWARE\Google\Chrome\DnsOverHttpsMode'
        Details: 'secure'
    selection_firefox:
        TargetObject|endswith: '\SOFTWARE\Policies\Mozilla\Firefox\DNSOverHTTPS\Enabled'
        Details: DWORD (0x00000001)
    condition: 1 of selection_*
falsepositives:
    - Unlikely
level: medium

Stages and Predicates

Stage 0: `condition`

1 of selection_*

Stage 1: `selection_edge`

selection_edge:
    TargetObject|endswith: '\SOFTWARE\Policies\Microsoft\Edge\BuiltInDnsClientEnabled'
    Details: DWORD (0x00000001)

Stage 2: `selection_chrome`

selection_chrome:
    TargetObject|endswith: '\SOFTWARE\Google\Chrome\DnsOverHttpsMode'
    Details: 'secure'

Stage 3: `selection_firefox`

selection_firefox:
    TargetObject|endswith: '\SOFTWARE\Policies\Mozilla\Firefox\DNSOverHTTPS\Enabled'
    Details: DWORD (0x00000001)

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`Details`	eq	`DWORD (0x00000001)` corpus 40 (sigma 36, chronicle 4) `secure` corpus 2 (sigma 1, elastic 1)
`TargetObject`	ends_with	`\SOFTWARE\Google\Chrome\DnsOverHttpsMode` corpus 2 (sigma 1, elastic 1) `\SOFTWARE\Policies\Microsoft\Edge\BuiltInDnsClientEnabled` corpus 2 (sigma 1, elastic 1) `\SOFTWARE\Policies\Mozilla\Firefox\DNSOverHTTPS\Enabled`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

DNS-over-HTTPS Enabled by Registry

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_edge`

Stage 2: `selection_chrome`

Stage 3: `selection_firefox`

Indicators

Keyboard shortcuts

Search operators

DNS-over-HTTPS Enabled by Registry

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_edge

Stage 2: selection_chrome

Stage 3: selection_firefox

Indicators

Stage 0: `condition`

Stage 1: `selection_edge`

Stage 2: `selection_chrome`

Stage 3: `selection_firefox`