DNS Query To Remote Access Software Domain From Non-Browser App

Status: test
Severity: medium
Log source: product windows, category dns_query
Author: frack113, Connor Martin
Source: github.com/SigmaHQ/sigma

An adversary may use legitimate desktop support and remote access software, such as Team Viewer, Go2Assist, LogMein, AmmyyAdmin, etc, to establish an interactive command and control channel to target systems within networks. These services are commonly used as legitimate technical support software, and may be allowed by application control within a target environment. Remote access tools like VNC, Ammyy, and Teamviewer are used frequently when compared with other legitimate software commonly used by adversaries. (Citation: Symantec Living off the Land)

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1219.002` Remote Access Tools: Remote Desktop Software

Event coverage

Provider	Event	Title
Sysmon	Event ID 22	DNSEvent (DNS query)

Rule body yaml

title: DNS Query To Remote Access Software Domain From Non-Browser App
id: 4d07b1f4-cb00-4470-b9f8-b0191d48ff52
related:
    - id: 71ba22cb-8a01-42e2-a6dd-5bf9b547498f
      type: obsolete
    - id: 7c4cf8e0-1362-48b2-a512-b606d2065d7d
      type: obsolete
    - id: ed785237-70fa-46f3-83b6-d264d1dc6eb4
      type: obsolete
status: test
description: |
    An adversary may use legitimate desktop support and remote access software, such as Team Viewer, Go2Assist, LogMein, AmmyyAdmin, etc, to establish an interactive command and control channel to target systems within networks.
    These services are commonly used as legitimate technical support software, and may be allowed by application control within a target environment.
    Remote access tools like VNC, Ammyy, and Teamviewer are used frequently when compared with other legitimate software commonly used by adversaries. (Citation: Symantec Living off the Land)
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1219/T1219.md#atomic-test-4---gotoassist-files-detected-test-on-windows
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1219/T1219.md#atomic-test-3---logmein-files-detected-test-on-windows
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1219/T1219.md#atomic-test-6---ammyy-admin-software-execution
    - https://redcanary.com/blog/misbehaving-rats/
    - https://techcommunity.microsoft.com/t5/microsoft-sentinel-blog/hunting-for-omi-vulnerability-exploitation-with-azure-sentinel/ba-p/2764093
    - https://www.cisa.gov/news-events/cybersecurity-advisories/aa23-320a
    - https://blog.sekoia.io/scattered-spider-laying-new-eggs/
    - https://learn.microsoft.com/en-us/windows/client-management/client-tools/quick-assist#disable-quick-assist-within-your-organization
author: frack113, Connor Martin
date: 2022-07-11
modified: 2024-12-17
tags:
    - attack.command-and-control
    - attack.t1219.002
logsource:
    product: windows
    category: dns_query
detection:
    selection_generic:
        QueryName|endswith:
            - 'agent.jumpcloud.com'
            - 'agentreporting.atera.com'
            - 'ammyy.com'
            - 'api.parsec.app'
            - 'api.playanext.com'
            - 'api.splashtop.com'
            - 'app.atera.com'
            - 'assist.zoho.com'
            - 'authentication.logmeininc.com'
            - 'beyondtrustcloud.com'
            - 'cdn.kaseya.net'
            - 'client.teamviewer.com'
            - 'comserver.corporate.beanywhere.com'
            - 'control.connectwise.com'
            - 'downloads.zohocdn.com'
            - 'dwservice.net'
            - 'express.gotoassist.com'
            - 'getgo.com'
            - 'getscreen.me'  # https://x.com/malmoeb/status/1868757130624614860?s=12&t=C0_T_re0wRP_NfKa27Xw9w
            - 'integratedchat.teamviewer.com'
            - 'join.zoho.com'
            - 'kickstart.jumpcloud.com'
            - 'license.bomgar.com'
            - 'logmein-gateway.com'
            - 'logmein.com'
            - 'logmeincdn.http.internapcdn.net'
            - 'n-able.com'
            - 'net.anydesk.com'
            - 'netsupportsoftware.com' # For NetSupport Manager RAT
            - 'parsecusercontent.com'
            - 'pubsub.atera.com'
            - 'relay.kaseya.net'
            - 'relay.screenconnect.com'
            - 'relay.splashtop.com'
            - 'remoteassistance.support.services.microsoft.com' # Quick Assist Application
            - 'remotedesktop-pa.googleapis.com'
            - 'remoteutilities.com' # Usage of Remote Utilities RAT
            - 'secure.logmeinrescue.com'
            - 'services.vnc.com'
            - 'static.remotepc.com'
            - 'swi-rc.com'
            - 'swi-tc.com'
            - 'tailscale.com' # Scattered Spider threat group used this RMM tool
            - 'telemetry.servers.qetqo.com'
            - 'tmate.io'
            - 'twingate.com'  # Scattered Spider threat group used this RMM tool
            - 'zohoassist.com'
    selection_rustdesk:  # https://twitter.com/malmoeb/status/1668504345132822531?s=20 and https://www.adamsdesk.com/posts/rustdesk-not-connecting/ mention this pattern
        QueryName|endswith: '.rustdesk.com'
        QueryName|startswith: 'rs-'
    # Exclude browsers for legitimate visits of the domains mentioned above
    # Add missing browsers you use and exclude the ones you don't
    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_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_safari:
        Image|endswith: '\safari.exe'
    filter_optional_defender:
        Image|endswith:
            - '\MsMpEng.exe' # Microsoft Defender executable
            - '\MsSense.exe' # Windows Defender Advanced Threat Protection Service Executable
    filter_optional_brave:
        Image|endswith: '\brave.exe'
        Image|startswith: 'C:\Program Files\BraveSoftware\'
    filter_optional_maxthon:
        Image|contains: '\AppData\Local\Maxthon\'
        Image|endswith: '\maxthon.exe'
    filter_optional_opera:
        Image|contains: '\AppData\Local\Programs\Opera\'
        Image|endswith: '\opera.exe'
    filter_optional_seamonkey:
        Image|startswith:
            - 'C:\Program Files\SeaMonkey\'
            - 'C:\Program Files (x86)\SeaMonkey\'
        Image|endswith: '\seamonkey.exe'
    filter_optional_vivaldi:
        Image|contains: '\AppData\Local\Vivaldi\'
        Image|endswith: '\vivaldi.exe'
    filter_optional_whale:
        Image|startswith:
            - 'C:\Program Files\Naver\Naver Whale\'
            - 'C:\Program Files (x86)\Naver\Naver Whale\'
        Image|endswith: '\whale.exe'
    filter_optional_tor:
        Image|contains: '\Tor Browser\'
    filter_optional_whaterfox:
        Image|startswith:
            - 'C:\Program Files\Waterfox\'
            - 'C:\Program Files (x86)\Waterfox\'
        Image|endswith: '\Waterfox.exe'
    filter_optional_midori:
        Image|contains: '\AppData\Local\Programs\midori-ng\'
        Image|endswith: '\Midori Next Generation.exe'
    filter_optional_slimbrowser:
        Image|startswith:
            - 'C:\Program Files\SlimBrowser\'
            - 'C:\Program Files (x86)\SlimBrowser\'
        Image|endswith: '\slimbrowser.exe'
    filter_optional_flock:
        Image|contains: '\AppData\Local\Flock\'
        Image|endswith: '\Flock.exe'
    filter_optional_phoebe:
        Image|contains: '\AppData\Local\Phoebe\'
        Image|endswith: '\Phoebe.exe'
    filter_optional_falkon:
        Image|startswith:
            - 'C:\Program Files\Falkon\'
            - 'C:\Program Files (x86)\Falkon\'
        Image|endswith: '\falkon.exe'
    filter_optional_avant:
        Image|startswith:
            - 'C:\Program Files (x86)\Avant Browser\'
            - 'C:\Program Files\Avant Browser\'
        Image|endswith: '\avant.exe'
    condition: 1 of selection_* and not 1 of filter_optional_*
falsepositives:
    - Likely with other browser software. Apply additional filters for any other browsers you might use.
level: medium

Stages and Predicates

Stage 0: `condition`

1 of selection_* and not 1 of filter_optional_*

Stage 1: `selection_generic`

selection_generic:
    QueryName|endswith:
        - 'agent.jumpcloud.com'
        - 'agentreporting.atera.com'
        - 'ammyy.com'
        - 'api.parsec.app'
        - 'api.playanext.com'
        - 'api.splashtop.com'
        - 'app.atera.com'
        - 'assist.zoho.com'
        - 'authentication.logmeininc.com'
        - 'beyondtrustcloud.com'
        - 'cdn.kaseya.net'
        - 'client.teamviewer.com'
        - 'comserver.corporate.beanywhere.com'
        - 'control.connectwise.com'
        - 'downloads.zohocdn.com'
        - 'dwservice.net'
        - 'express.gotoassist.com'
        - 'getgo.com'
        - 'getscreen.me'
        - 'integratedchat.teamviewer.com'
        - 'join.zoho.com'
        - 'kickstart.jumpcloud.com'
        - 'license.bomgar.com'
        - 'logmein-gateway.com'
        - 'logmein.com'
        - 'logmeincdn.http.internapcdn.net'
        - 'n-able.com'
        - 'net.anydesk.com'
        - 'netsupportsoftware.com'
        - 'parsecusercontent.com'
        - 'pubsub.atera.com'
        - 'relay.kaseya.net'
        - 'relay.screenconnect.com'
        - 'relay.splashtop.com'
        - 'remoteassistance.support.services.microsoft.com'
        - 'remotedesktop-pa.googleapis.com'
        - 'remoteutilities.com'
        - 'secure.logmeinrescue.com'
        - 'services.vnc.com'
        - 'static.remotepc.com'
        - 'swi-rc.com'
        - 'swi-tc.com'
        - 'tailscale.com'
        - 'telemetry.servers.qetqo.com'
        - 'tmate.io'
        - 'twingate.com'
        - 'zohoassist.com'

Stage 2: `selection_rustdesk`

selection_rustdesk:
    QueryName|endswith: '.rustdesk.com'
    QueryName|startswith: 'rs-'

Stage 3: `not filter_optional_*`

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_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_safari:
    Image|endswith: '\safari.exe'
filter_optional_defender:
    Image|endswith:
        - '\MsMpEng.exe'
        - '\MsSense.exe'
filter_optional_brave:
    Image|endswith: '\brave.exe'
    Image|startswith: 'C:\Program Files\BraveSoftware\'
filter_optional_maxthon:
    Image|contains: '\AppData\Local\Maxthon\'
    Image|endswith: '\maxthon.exe'
filter_optional_opera:
    Image|contains: '\AppData\Local\Programs\Opera\'
    Image|endswith: '\opera.exe'
filter_optional_seamonkey:
    Image|startswith:
        - 'C:\Program Files\SeaMonkey\'
        - 'C:\Program Files (x86)\SeaMonkey\'
    Image|endswith: '\seamonkey.exe'
filter_optional_vivaldi:
    Image|contains: '\AppData\Local\Vivaldi\'
    Image|endswith: '\vivaldi.exe'
filter_optional_whale:
    Image|startswith:
        - 'C:\Program Files\Naver\Naver Whale\'
        - 'C:\Program Files (x86)\Naver\Naver Whale\'
    Image|endswith: '\whale.exe'
filter_optional_tor:
    Image|contains: '\Tor Browser\'
filter_optional_whaterfox:
    Image|startswith:
        - 'C:\Program Files\Waterfox\'
        - 'C:\Program Files (x86)\Waterfox\'
    Image|endswith: '\Waterfox.exe'
filter_optional_midori:
    Image|contains: '\AppData\Local\Programs\midori-ng\'
    Image|endswith: '\Midori Next Generation.exe'
filter_optional_slimbrowser:
    Image|startswith:
        - 'C:\Program Files\SlimBrowser\'
        - 'C:\Program Files (x86)\SlimBrowser\'
    Image|endswith: '\slimbrowser.exe'
filter_optional_flock:
    Image|contains: '\AppData\Local\Flock\'
    Image|endswith: '\Flock.exe'
filter_optional_phoebe:
    Image|contains: '\AppData\Local\Phoebe\'
    Image|endswith: '\Phoebe.exe'
filter_optional_falkon:
    Image|startswith:
        - 'C:\Program Files\Falkon\'
        - 'C:\Program Files (x86)\Falkon\'
    Image|endswith: '\falkon.exe'
filter_optional_avant:
    Image|startswith:
        - 'C:\Program Files (x86)\Avant Browser\'
        - 'C:\Program Files\Avant Browser\'
    Image|endswith: '\avant.exe'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`Image`	ends_with	`\msedge.exe`
`Image`	ends_with	`\msedgewebview2.exe`
`Image`	starts_with	`C:\Program Files (x86)\Microsoft\EdgeCore\`
`Image`	starts_with	`C:\Program Files\Microsoft\EdgeCore\`
`Image`	starts_with	`C:\Program Files (x86)\Avant Browser\`
`Image`	starts_with	`C:\Program Files\Avant Browser\`
`Image`	ends_with	`\avant.exe`
`Image`	starts_with	`C:\Program Files (x86)\Falkon\`
`Image`	starts_with	`C:\Program Files\Falkon\`
`Image`	ends_with	`\falkon.exe`
`Image`	starts_with	`C:\Program Files (x86)\Naver\Naver Whale\`
`Image`	starts_with	`C:\Program Files\Naver\Naver Whale\`
`Image`	ends_with	`\whale.exe`
`Image`	starts_with	`C:\Program Files (x86)\SeaMonkey\`
`Image`	starts_with	`C:\Program Files\SeaMonkey\`
`Image`	ends_with	`\seamonkey.exe`
`Image`	starts_with	`C:\Program Files (x86)\SlimBrowser\`
`Image`	starts_with	`C:\Program Files\SlimBrowser\`
`Image`	ends_with	`\slimbrowser.exe`
`Image`	starts_with	`C:\Program Files (x86)\Waterfox\`
`Image`	starts_with	`C:\Program Files\Waterfox\`
`Image`	ends_with	`\Waterfox.exe`
`Image`	ends_with	`\Flock.exe`
`Image`	match	`\AppData\Local\Flock\`
`Image`	ends_with	`\Midori Next Generation.exe`
`Image`	match	`\AppData\Local\Programs\midori-ng\`
`Image`	ends_with	`\Phoebe.exe`
`Image`	match	`\AppData\Local\Phoebe\`
`Image`	ends_with	`\brave.exe`
`Image`	starts_with	`C:\Program Files\BraveSoftware\`
`Image`	ends_with	`\maxthon.exe`
`Image`	match	`\AppData\Local\Maxthon\`
`Image`	ends_with	`\opera.exe`
`Image`	match	`\AppData\Local\Programs\Opera\`
`Image`	ends_with	`\vivaldi.exe`
`Image`	match	`\AppData\Local\Vivaldi\`
`Image`	ends_with	`\MsMpEng.exe`
`Image`	ends_with	`\MsSense.exe`
`Image`	ends_with	`\WindowsApps\MicrosoftEdge.exe`
`Image`	ends_with	`\safari.exe`
`Image`	eq	`C:\Program Files (x86)\Google\Chrome\Application\chrome.exe`
`Image`	eq	`C:\Program Files (x86)\Internet Explorer\iexplore.exe`
`Image`	eq	`C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe`
`Image`	eq	`C:\Program Files (x86)\Mozilla Firefox\firefox.exe`
`Image`	eq	`C:\Program Files\Google\Chrome\Application\chrome.exe`
`Image`	eq	`C:\Program Files\Internet Explorer\iexplore.exe`
`Image`	eq	`C:\Program Files\Microsoft\Edge\Application\msedge.exe`
`Image`	eq	`C:\Program Files\Mozilla Firefox\firefox.exe`
`Image`	match	`\Tor Browser\`
`Image`	starts_with	`C:\Program Files (x86)\Microsoft\EdgeWebView\Application\`

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
`QueryName`	ends_with	`.rustdesk.com` `agent.jumpcloud.com` `agentreporting.atera.com` `ammyy.com` `api.parsec.app` `api.playanext.com` `api.splashtop.com` `app.atera.com` `assist.zoho.com` `authentication.logmeininc.com` `beyondtrustcloud.com` `cdn.kaseya.net` `client.teamviewer.com` `comserver.corporate.beanywhere.com` `control.connectwise.com` `downloads.zohocdn.com` `dwservice.net` `express.gotoassist.com` `getgo.com` `getscreen.me` `integratedchat.teamviewer.com` `join.zoho.com` `kickstart.jumpcloud.com` `license.bomgar.com` `logmein-gateway.com` `logmein.com` `logmeincdn.http.internapcdn.net` `n-able.com` `net.anydesk.com` `netsupportsoftware.com` `parsecusercontent.com` `pubsub.atera.com` `relay.kaseya.net` `relay.screenconnect.com` `relay.splashtop.com` `remoteassistance.support.services.microsoft.com` corpus 2 (sigma 2) `remotedesktop-pa.googleapis.com` `remoteutilities.com` `secure.logmeinrescue.com` `services.vnc.com` `static.remotepc.com` `swi-rc.com` `swi-tc.com` `tailscale.com` `telemetry.servers.qetqo.com` `tmate.io` `twingate.com` `zohoassist.com`
`QueryName`	starts_with	`rs-`

`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 Query To Remote Access Software Domain From Non-Browser App

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_generic`

Stage 2: `selection_rustdesk`

Stage 3: `not filter_optional_*`

Exclusions

Indicators

Keyboard shortcuts

Search operators

DNS Query To Remote Access Software Domain From Non-Browser App

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_generic

Stage 2: selection_rustdesk

Stage 3: not filter_optional_*

Exclusions

Indicators

Stage 0: `condition`

Stage 1: `selection_generic`

Stage 2: `selection_rustdesk`

Stage 3: `not filter_optional_*`