Elevated System Shell Spawned From Uncommon Parent Location

Status: test
Severity: medium
Log source: product windows, category process_creation
Author: frack113, Tim Shelton (update fp)
Source: github.com/SigmaHQ/sigma

Detects when a shell program such as the Windows command prompt or PowerShell is launched with system privileges from a uncommon parent location.

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059` Command and Scripting Interpreter

Event coverage

Provider	Event	Title
Sysmon	Event ID 1	Process creation

Rule body yaml

title: Elevated System Shell Spawned From Uncommon Parent Location
id: 178e615d-e666-498b-9630-9ed363038101
related:
    - id: 61065c72-5d7d-44ef-bf41-6a36684b545f
      type: similar
status: test
description: Detects when a shell program such as the Windows command prompt or PowerShell is launched with system privileges from a uncommon parent location.
references:
    - https://github.com/Wh04m1001/SysmonEoP
author: frack113, Tim Shelton (update fp)
date: 2022-12-05
modified: 2025-03-06
tags:
    - attack.privilege-escalation
    - attack.execution
    - attack.t1059
logsource:
    product: windows
    category: process_creation
detection:
    selection_shell:
        - Image|endswith:
              - '\powershell.exe'
              - '\powershell_ise.exe'
              - '\pwsh.exe'
              - '\cmd.exe'
        - OriginalFileName:
              - 'PowerShell.EXE'
              - 'powershell_ise.EXE'
              - 'pwsh.dll'
              - 'Cmd.Exe'
    selection_user:
        User|contains: # covers many language settings
            - 'AUTHORI'
            - 'AUTORI'
        LogonId: '0x3e7'
    filter_main_generic:
        # Example 1:
        #   C:\Program Files\erl-23.2\erts-11.1.4\bin\erl.exe" -service_event ErlSrv_RabbitMQ -nohup -sname rabbit@localhost -s rabbit boot -boot start_sasl +W w +MBas ageffcbf +MHas ageffcbf +MBlmbcs 512 +MHlmbcs 512 +MMmcs 30 +P 1048576 +t 5000000 +stbt db +zdbbl 128000 +sbwt none +sbwtdcpu none +sbwtdio none -kernel inet_dist_listen_min 25672 -kernel inet_dist_listen_max 25672 -lager crash_log false -lager handlers []
        # Example 2:
        #   ParentImage: C:\Program Files (x86)\Varonis\DatAdvantage\GridCollector\VrnsRealTimeAlertsSvc.exe" /appid 000000ad-cb03-500b-9459-c46d000000ad
        #   CommandLine: C:\Windows\system32\cmd.exe /c C:\Program Files "(x86)\Varonis\DatAdvantage\GridCollector\handle_scopes.cmd C:\Collector" Working Share\VaronisWorkDirectoryCollector
        ParentImage|contains:
            - ':\Program Files (x86)\'
            - ':\Program Files\'
            - ':\ProgramData\'
            - ':\Windows\System32\'
            - ':\Windows\SysWOW64\'
            - ':\Windows\Temp\' # Installers
            - ':\Windows\WinSxS\'
    filter_optional_manageengine:
        # Example:
        #   ParentImage: C:/ManageEngine/ADManager Plus/pgsql/bin/postgres.exe" --forkarch 5380
        #   CommandLine: C:\Windows\system32\cmd.exe /c "IF EXIST archive.bat (archive.bat pg_wal\000000010000008E000000EA 000000010000008E000000EA)
        ParentImage|endswith: ':\ManageEngine\ADManager Plus\pgsql\bin\postgres.exe'
        Image|endswith: '\cmd.exe'
    filter_optional_asgard:
        CommandLine|contains: ':\WINDOWS\system32\cmd.exe /c "'
        CurrentDirectory|contains: ':\WINDOWS\Temp\asgard2-agent\'
    filter_optional_ibm_spectrumprotect:
        ParentImage|contains: ':\IBM\SpectrumProtect\webserver\scripts\'
        CommandLine|contains: ':\IBM\SpectrumProtect\webserver\scripts\'
    filter_main_parent_null:
        ParentImage: null
    filter_main_parent_empty:
        ParentImage:
            - ''
            - '-'
    condition: all of selection_* and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Some legitimate applications may spawn shells from uncommon parent locations. Apply additional filters and perform an initial baseline before deploying.
level: medium

Stages and Predicates

Stage 0: `condition`

all of selection_* and not 1 of filter_main_* and not 1 of filter_optional_*

Stage 1: `selection_shell`

selection_shell:
    - Image|endswith:
          - '\powershell.exe'
          - '\powershell_ise.exe'
          - '\pwsh.exe'
          - '\cmd.exe'
    - OriginalFileName:
          - 'PowerShell.EXE'
          - 'powershell_ise.EXE'
          - 'pwsh.dll'
          - 'Cmd.Exe'

Stage 2: `selection_user`

selection_user:
    User|contains:
        - 'AUTHORI'
        - 'AUTORI'
    LogonId: '0x3e7'

Stage 3: `not filter_main_*`

filter_main_generic:
    ParentImage|contains:
        - ':\Program Files (x86)\'
        - ':\Program Files\'
        - ':\ProgramData\'
        - ':\Windows\System32\'
        - ':\Windows\SysWOW64\'
        - ':\Windows\Temp\'
        - ':\Windows\WinSxS\'
filter_main_parent_null:
    ParentImage: null
filter_main_parent_empty:
    ParentImage:
        - ''
        - '-'

Stage 4: `not filter_optional_*`

filter_optional_manageengine:
    ParentImage|endswith: ':\ManageEngine\ADManager Plus\pgsql\bin\postgres.exe'
    Image|endswith: '\cmd.exe'
filter_optional_asgard:
    CommandLine|contains: ':\WINDOWS\system32\cmd.exe /c "'
    CurrentDirectory|contains: ':\WINDOWS\Temp\asgard2-agent\'
filter_optional_ibm_spectrumprotect:
    ParentImage|contains: ':\IBM\SpectrumProtect\webserver\scripts\'
    CommandLine|contains: ':\IBM\SpectrumProtect\webserver\scripts\'

Exclusions

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

Field	Kind	Excluded values
`ParentImage`	eq	`-`
`ParentImage`	is_null	(no value, null check)
`ParentImage`	match	`:\Program Files (x86)\`
`ParentImage`	match	`:\Program Files\`
`ParentImage`	match	`:\ProgramData\`
`ParentImage`	match	`:\Windows\SysWOW64\`
`ParentImage`	match	`:\Windows\System32\`
`ParentImage`	match	`:\Windows\Temp\`
`ParentImage`	match	`:\Windows\WinSxS\`
`CommandLine`	match	`:\IBM\SpectrumProtect\webserver\scripts\`
`ParentImage`	match	`:\IBM\SpectrumProtect\webserver\scripts\`
`CommandLine`	match	`:\WINDOWS\system32\cmd.exe /c "`
`CurrentDirectory`	match	`:\WINDOWS\Temp\asgard2-agent\`
`Image`	ends_with	`\cmd.exe`
`ParentImage`	ends_with	`:\ManageEngine\ADManager Plus\pgsql\bin\postgres.exe`

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
`Image`	ends_with	`\cmd.exe` corpus 130 (sigma 130) `\powershell.exe` corpus 182 (sigma 182) `\powershell_ise.exe` corpus 41 (sigma 41) `\pwsh.exe` corpus 168 (sigma 168)
`LogonId`	eq	`0x3e7` corpus 2 (sigma 2)
`OriginalFileName`	eq	`Cmd.Exe` corpus 65 (sigma 43, splunk 17, elastic 5) `PowerShell.EXE` corpus 120 (sigma 84, splunk 30, elastic 6) `powershell_ise.EXE` corpus 51 (splunk 30, sigma 18, elastic 3) `pwsh.dll` corpus 112 (sigma 79, splunk 30, elastic 3)
`User`	match	`AUTHORI` corpus 14 (sigma 14) `AUTORI` corpus 14 (sigma 14)

`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)

Elevated System Shell Spawned From Uncommon Parent Location

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_shell`

Stage 2: `selection_user`

Stage 3: `not filter_main_*`

Stage 4: `not filter_optional_*`

Exclusions

Indicators

Keyboard shortcuts

Search operators

Elevated System Shell Spawned From Uncommon Parent Location

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_shell

Stage 2: selection_user

Stage 3: not filter_main_*

Stage 4: not filter_optional_*

Exclusions

Indicators

Stage 0: `condition`

Stage 1: `selection_shell`

Stage 2: `selection_user`

Stage 3: `not filter_main_*`

Stage 4: `not filter_optional_*`