Alternate PowerShell Hosts Pipe

Status: test
Severity: medium
Log source: product windows, category pipe_created
Author: Roberto Rodriguez @Cyb3rWard0g, Tim Shelton
Source: github.com/SigmaHQ/sigma

Detects alternate PowerShell hosts potentially bypassing detections looking for powershell.exe

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059.001` Command and Scripting Interpreter: PowerShell

Event coverage

Provider	Event	Title
Sysmon	Event ID 17	PipeEvent (Pipe Created)
Sysmon	Event ID 18	PipeEvent (Pipe Connected)

Rule body yaml

title: Alternate PowerShell Hosts Pipe
id: 58cb02d5-78ce-4692-b3e1-dce850aae41a
related:
    - id: ac7102b4-9e1e-4802-9b4f-17c5524c015c
      type: derived
status: test
description: Detects alternate PowerShell hosts potentially bypassing detections looking for powershell.exe
references:
    - https://threathunterplaybook.com/hunts/windows/190610-PwshAlternateHosts/notebook.html
    - https://threathunterplaybook.com/hunts/windows/190410-LocalPwshExecution/notebook.html
author: Roberto Rodriguez @Cyb3rWard0g, Tim Shelton
date: 2019-09-12
modified: 2025-10-07
tags:
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    category: pipe_created
    definition: 'Note that you have to configure logging for Named Pipe Events in Sysmon config (Event ID 17 and Event ID 18). The basic configuration is in popular sysmon configuration (https://github.com/SwiftOnSecurity/sysmon-config), but it is worth verifying. You can also use other repo, e.g. https://github.com/Neo23x0/sysmon-config, https://github.com/olafhartong/sysmon-modular. How to test detection? You can check powershell script from this site https://svch0st.medium.com/guide-to-named-pipes-and-hunting-for-cobalt-strike-pipes-dc46b2c5f575'
detection:
    selection:
        PipeName|startswith: '\PSHost'
    filter_main_generic:
        - Image|contains:
              - ':\Program Files\PowerShell\7-preview\pwsh.exe' # Powershell 7
              - ':\Program Files\PowerShell\7\pwsh.exe' # Powershell 7
              - ':\Windows\system32\dsac.exe'
              - ':\Windows\system32\inetsrv\w3wp.exe'   # this is sad :,( but it triggers FPs on Exchange servers
              - ':\Windows\System32\sdiagnhost.exe'
              - ':\Windows\system32\ServerManager.exe'
              - ':\Windows\system32\wbem\wmiprvse.exe'
              - ':\Windows\System32\WindowsPowerShell\v1.0\powershell_ise.exe'
              - ':\Windows\System32\WindowsPowerShell\v1.0\powershell.exe'
              - ':\Windows\System32\wsmprovhost.exe'
              - ':\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell_ise.exe'
              - ':\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe'
        - Image|contains|all:
              - 'C:\Program Files\WindowsApps\Microsoft.PowerShellPreview'
              - '\pwsh.exe'
        - Image|contains|all:
              - '\AppData\Local\Microsoft\WindowsApps\Microsoft.PowerShellPreview'
              - '\pwsh.exe'
    filter_optional_sqlserver: # Microsoft SQL Server\130\Tools\
        Image|startswith:
            - 'C:\Program Files (x86)\'
            - 'C:\Program Files\'
        Image|contains: '\Microsoft SQL Server\'
        Image|endswith: '\Tools\Binn\SQLPS.exe'
    filter_optional_azure_connected_machine_agent:
        # Azure Connected Machine Agent (https://devblogs.microsoft.com/powershell/azure-policy-guest-configuration-client/)
        Image|startswith: 'C:\Program Files\AzureConnectedMachineAgent\GCArcService'
        Image|endswith: '\GC\gc_worker.exe'
    filter_optional_citrix:
        Image|startswith: 'C:\Program Files\Citrix\'
    filter_optional_exchange:
        Image|startswith: 'C:\Program Files\Microsoft\Exchange Server\'
    filter_main_null:
        Image: null
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Programs using PowerShell directly without invocation of a dedicated interpreter.
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:
    PipeName|startswith: '\PSHost'

Stage 2: `not filter_main_*`

filter_main_generic:
    - Image|contains:
          - ':\Program Files\PowerShell\7-preview\pwsh.exe'
          - ':\Program Files\PowerShell\7\pwsh.exe'
          - ':\Windows\system32\dsac.exe'
          - ':\Windows\system32\inetsrv\w3wp.exe'
          - ':\Windows\System32\sdiagnhost.exe'
          - ':\Windows\system32\ServerManager.exe'
          - ':\Windows\system32\wbem\wmiprvse.exe'
          - ':\Windows\System32\WindowsPowerShell\v1.0\powershell_ise.exe'
          - ':\Windows\System32\WindowsPowerShell\v1.0\powershell.exe'
          - ':\Windows\System32\wsmprovhost.exe'
          - ':\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell_ise.exe'
          - ':\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe'
    - Image|contains|all:
          - 'C:\Program Files\WindowsApps\Microsoft.PowerShellPreview'
          - '\pwsh.exe'
    - Image|contains|all:
          - '\AppData\Local\Microsoft\WindowsApps\Microsoft.PowerShellPreview'
          - '\pwsh.exe'
filter_main_null:
    Image: null

Stage 3: `not filter_optional_*`

filter_optional_sqlserver:
    Image|startswith:
        - 'C:\Program Files (x86)\'
        - 'C:\Program Files\'
    Image|contains: '\Microsoft SQL Server\'
    Image|endswith: '\Tools\Binn\SQLPS.exe'
filter_optional_azure_connected_machine_agent:
    Image|startswith: 'C:\Program Files\AzureConnectedMachineAgent\GCArcService'
    Image|endswith: '\GC\gc_worker.exe'
filter_optional_citrix:
    Image|startswith: 'C:\Program Files\Citrix\'
filter_optional_exchange:
    Image|startswith: 'C:\Program Files\Microsoft\Exchange Server\'

Exclusions

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

Field	Kind	Excluded values
`Image`	match	`C:\Program Files\WindowsApps\Microsoft.PowerShellPreview`
`Image`	match	`\pwsh.exe`
`Image`	match	`\AppData\Local\Microsoft\WindowsApps\Microsoft.PowerShellPreview`
`Image`	match	`\pwsh.exe`
`Image`	is_null	(no value, null check)
`Image`	match	`:\Program Files\PowerShell\7-preview\pwsh.exe`
`Image`	match	`:\Program Files\PowerShell\7\pwsh.exe`
`Image`	match	`:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe`
`Image`	match	`:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell_ise.exe`
`Image`	match	`:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe`
`Image`	match	`:\Windows\System32\WindowsPowerShell\v1.0\powershell_ise.exe`
`Image`	match	`:\Windows\System32\sdiagnhost.exe`
`Image`	match	`:\Windows\System32\wsmprovhost.exe`
`Image`	match	`:\Windows\system32\ServerManager.exe`
`Image`	match	`:\Windows\system32\dsac.exe`
`Image`	match	`:\Windows\system32\inetsrv\w3wp.exe`
`Image`	match	`:\Windows\system32\wbem\wmiprvse.exe`
`Image`	starts_with	`C:\Program Files (x86)\`
`Image`	starts_with	`C:\Program Files\`
`Image`	ends_with	`\Tools\Binn\SQLPS.exe`
`Image`	match	`\Microsoft SQL Server\`
`Image`	ends_with	`\GC\gc_worker.exe`
`Image`	starts_with	`C:\Program Files\AzureConnectedMachineAgent\GCArcService`
`Image`	starts_with	`C:\Program Files\Citrix\`
`Image`	starts_with	`C:\Program Files\Microsoft\Exchange Server\`

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
`PipeName`	starts_with	`\PSHost` corpus 2 (sigma 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:`)
`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)

Alternate PowerShell Hosts Pipe

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

Indicators

Keyboard shortcuts

Search operators

Alternate PowerShell Hosts Pipe

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

Indicators

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter_main_*`

Stage 3: `not filter_optional_*`