AppX Located in Uncommon Directory Added to Deployment Pipeline

Status: test
Severity: medium
Log source: product windows, service appxdeployment-server
Author: Nasreddine Bencherchali (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects an appx package that was added to the pipeline of the "to be processed" packages that is located in uncommon locations.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	No specific technique

Event coverage

Provider	Event	Title
AppXDeployment-Server	Event ID 854	Successfully added the following uri(s) to be processed: Path.

Rule body yaml

title: AppX Located in Uncommon Directory Added to Deployment Pipeline
id: c977cb50-3dff-4a9f-b873-9290f56132f1
status: test
description: |
    Detects an appx package that was added to the pipeline of the "to be processed" packages that is located in uncommon locations.
references:
    - Internal Research
    - https://www.sentinelone.com/labs/inside-malicious-windows-apps-for-malware-deployment/
    - https://learn.microsoft.com/en-us/windows/win32/appxpkg/troubleshooting
    - https://news.sophos.com/en-us/2021/11/11/bazarloader-call-me-back-attack-abuses-windows-10-apps-mechanism/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-01-11
modified: 2025-12-03
tags:
    - attack.stealth
logsource:
    product: windows
    service: appxdeployment-server
detection:
    selection:
        EventID: 854
    filter_main_generic:
        Path|contains:
            # Paths can be written using forward slash if the "file://" protocol is used
            - ':/Program%20Files' # Also covers 'file:///C:/Program%20Files%20(x86)/'
            - ':/Windows/System32/'
            - ':\Program Files (x86)\'
            - ':\Program Files\'
            - ':\Windows\ImmersiveControlPanel\'
            - ':\Windows\PrintDialog\'
            - ':\Windows\SystemApps\'
            - 'AppData/Local/Temp/WinGet/Microsoft.Winget.Source'
            - 'x-windowsupdate://'
    filter_main_specific:
        Path|contains:
            - 'https://installer.teams.static.microsoft/'
            - 'https://res.cdn.office.net' # Example https://res.cdn.office.net/nativehost/5mttl/installer/v2/1.2025.617.100/Microsoft.OutlookForWindows_x64.msix
            - 'https://statics.teams.cdn.live.net/'
            - 'https://statics.teams.cdn.office.net/'
            - 'microsoft.com' # Example: https://go.microsoft.com/fwlink/?linkid=2160968
    filter_optional_onedrive:
        Path|contains: 'AppData\Local\Microsoft\OneDrive\'
    filter_optional_winget:
        Path|contains:
            - 'AppData/Local/Temp/WinGet/Microsoft.Winget.Source'
            - 'AppData\Local\Temp\WinGet\Microsoft.Winget.Source'
    filter_optional_x_windowsupdate:
        Path|contains: 'x-windowsupdate://'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: `condition`

selection and not 1 of filter_main_* and not 1 of filter_optional_*

Stage 1: `selection`

selection:
    EventID: 854

Stage 2: `not filter_main_*`

filter_main_generic:
    Path|contains:
        - ':/Program%20Files'
        - ':/Windows/System32/'
        - ':\Program Files (x86)\'
        - ':\Program Files\'
        - ':\Windows\ImmersiveControlPanel\'
        - ':\Windows\PrintDialog\'
        - ':\Windows\SystemApps\'
        - 'AppData/Local/Temp/WinGet/Microsoft.Winget.Source'
        - 'x-windowsupdate://'
filter_main_specific:
    Path|contains:
        - 'https://installer.teams.static.microsoft/'
        - 'https://res.cdn.office.net'
        - 'https://statics.teams.cdn.live.net/'
        - 'https://statics.teams.cdn.office.net/'
        - 'microsoft.com'

Stage 3: `not filter_optional_*`

filter_optional_onedrive:
    Path|contains: 'AppData\Local\Microsoft\OneDrive\'
filter_optional_winget:
    Path|contains:
        - 'AppData/Local/Temp/WinGet/Microsoft.Winget.Source'
        - 'AppData\Local\Temp\WinGet\Microsoft.Winget.Source'
filter_optional_x_windowsupdate:
    Path|contains: 'x-windowsupdate://'

Exclusions

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

Field	Kind	Excluded values
`Path`	match	`:/Program%20Files`
`Path`	match	`:/Windows/System32/`
`Path`	match	`:\Program Files (x86)\`
`Path`	match	`:\Program Files\`
`Path`	match	`:\Windows\ImmersiveControlPanel\`
`Path`	match	`:\Windows\PrintDialog\`
`Path`	match	`:\Windows\SystemApps\`
`Path`	match	`AppData/Local/Temp/WinGet/Microsoft.Winget.Source`
`Path`	match	`https://installer.teams.static.microsoft/`
`Path`	match	`https://res.cdn.office.net`
`Path`	match	`https://statics.teams.cdn.live.net/`
`Path`	match	`https://statics.teams.cdn.office.net/`
`Path`	match	`microsoft.com`
`Path`	match	`x-windowsupdate://`
`Path`	match	`AppData/Local/Temp/WinGet/Microsoft.Winget.Source`
`Path`	match	`AppData\Local\Microsoft\OneDrive\`
`Path`	match	`AppData\Local\Temp\WinGet\Microsoft.Winget.Source`
`Path`	match	`x-windowsupdate://`

`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)

AppX Located in Uncommon Directory Added to Deployment Pipeline

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter_main_*`

Stage 3: `not filter_optional_*`

Exclusions

Keyboard shortcuts

Search operators

AppX Located in Uncommon Directory Added to Deployment Pipeline

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection

Stage 2: not filter_main_*

Stage 3: not filter_optional_*

Exclusions

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter_main_*`

Stage 3: `not filter_optional_*`