Registry Modification of MS-settings Protocol Handler

Status: test
Severity: medium
Author: frack113, Swachchhanda Shrawan Poudel (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects registry modifications to the 'ms-settings' protocol handler, which is frequently targeted for UAC bypass or persistence. Attackers can modify this registry to execute malicious code with elevated privileges by hijacking the command execution path.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1112` Modify Registry, `T1546.001` Event Triggered Execution: Change Default File Association
Privilege Escalation	`T1546.001` Event Triggered Execution: Change Default File Association, `T1548.002` Abuse Elevation Control Mechanism: Bypass User Account Control
Defense Impairment	`T1112` Modify Registry

Event coverage

Provider	Event	Title
Sysmon	Event ID 1	Process creation

Rule body yaml

title: Registry Modification of MS-settings Protocol Handler
id: dd3ee8cc-f751-41c9-ba53-5a32ed47e563
related:
    - id: 152f3630-77c1-4284-bcc0-4cc68ab2f6e7
      type: similar
status: test
description: |
    Detects registry modifications to the 'ms-settings' protocol handler, which is frequently targeted for UAC bypass or persistence.
    Attackers can modify this registry to execute malicious code with elevated privileges by hijacking the command execution path.
references:
    - https://thedfirreport.com/2021/12/13/diavol-ransomware/
    - https://www.trendmicro.com/en_us/research/25/f/water-curse.html
author: frack113, Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2021-12-20
modified: 2026-01-24
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.defense-impairment
    - attack.t1548.002
    - attack.t1546.001
    - attack.t1112
logsource:
    category: process_creation
    product: windows
detection:
    selection_reg_img:
        - Image|endswith: '\reg.exe'
        - OriginalFileName: 'reg.exe'
    selection_pwsh_img:
        - Image|endswith:
              - '\powershell.exe'
              - '\pwsh.exe'
        - OriginalFileName:
              - 'powershell.exe'
              - 'pwsh.dll'
    selection_reg_cli:
        CommandLine|contains: 'add'
    selection_pwsh_cli:
        CommandLine|contains:
            - 'New-ItemProperty'
            - 'Set-ItemProperty'
            - 'ni '
            - 'sp '
    selection_cli_key:
        CommandLine|contains: '\ms-settings\shell\open\command'
    condition: (all of selection_reg_* or all of selection_pwsh_*) and selection_cli_key
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: `condition`

(all of selection_reg_* or all of selection_pwsh_*) and selection_cli_key

Stage 1: `selection_reg_img`

selection_reg_img:
    - Image|endswith: '\reg.exe'
    - OriginalFileName: 'reg.exe'

Stage 2: `selection_reg_cli`

selection_reg_cli:
    CommandLine|contains: 'add'

Stage 3: `selection_pwsh_img`

selection_pwsh_img:
    - Image|endswith:
          - '\powershell.exe'
          - '\pwsh.exe'
    - OriginalFileName:
          - 'powershell.exe'
          - 'pwsh.dll'

Stage 4: `selection_pwsh_cli`

selection_pwsh_cli:
    CommandLine|contains:
        - 'New-ItemProperty'
        - 'Set-ItemProperty'
        - 'ni '
        - 'sp '

Stage 5: `selection_cli_key`

selection_cli_key:
    CommandLine|contains: '\ms-settings\shell\open\command'

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
`CommandLine`	match	`New-ItemProperty` corpus 7 (sigma 7) `Set-ItemProperty` corpus 7 (sigma 7) `\ms-settings\shell\open\command` `add` corpus 36 (sigma 28, splunk 4, chronicle 2, kusto 2) `ni` corpus 2 (sigma 2) `sp` corpus 2 (sigma 2)
`Image`	ends_with	`\powershell.exe` corpus 186 (sigma 186) `\pwsh.exe` corpus 172 (sigma 172) `\reg.exe` corpus 60 (sigma 60)
`OriginalFileName`	eq	`powershell.exe` corpus 121 (sigma 85, splunk 30, elastic 6) `pwsh.dll` corpus 112 (sigma 79, splunk 30, elastic 3) `reg.exe` corpus 42 (sigma 32, splunk 8, elastic 2)

`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:`)
`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)

Registry Modification of MS-settings Protocol Handler

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_reg_img`

Stage 2: `selection_reg_cli`

Stage 3: `selection_pwsh_img`

Stage 4: `selection_pwsh_cli`

Stage 5: `selection_cli_key`

Indicators

Keyboard shortcuts

Search operators

Registry Modification of MS-settings Protocol Handler

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_reg_img

Stage 2: selection_reg_cli

Stage 3: selection_pwsh_img

Stage 4: selection_pwsh_cli

Stage 5: selection_cli_key

Indicators

Stage 0: `condition`

Stage 1: `selection_reg_img`

Stage 2: `selection_reg_cli`

Stage 3: `selection_pwsh_img`

Stage 4: `selection_pwsh_cli`

Stage 5: `selection_cli_key`