PowerShell PInvoke Process Injection API Chain

name: PowerShell PInvoke Process Injection API Chain
id: 3f1a2b4c-d5e6-7890-abcd-ef1234567890
version: 3
creation_date: '2026-04-29'
modification_date: '2026-06-25'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: |
    The following analytic detects PowerShell Script Block Logging (Event ID 4104) evidence of a complete P/Invoke process-injection API chain at either the compile phase or the execution phase.
    Portions of this search were modified to retain the same functionality while preventing antivirus products from alerting on the detection itself
data_source:
    - Powershell Script Block Logging 4104
search: |-
    `powershell`
    EventCode=4104
    ScriptBlockText="*add-type*"
    ScriptBlockText="*DllImport*"
    ScriptBlockText IN (
        "*extern IntPtr*",
        "*extern bool*",
        "*extern uint*",
        "*extern int*"
    )
    | where
        (
            match(ScriptBlockText, "(?i)[v][i][r][t][u][a][l][a][l][l][o][c]")
            AND match(ScriptBlockText, "(?i)[v][i][r][t][u][a][l][p][r][o][t][e][c][t]")
            AND match(ScriptBlockText, "(?i)[c][r][e][a][t][e][t][h][r][e][a][d]")
        )
        OR
        (
            match(ScriptBlockText, "(?i)[o][p][e][n][p][r][o][c][e][s][s]")
            AND match(ScriptBlockText, "(?i)[v][i][r][t][u][a][l][a][l][l][o][c]")
            AND match(ScriptBlockText, "(?i)[w][r][i][t][e][p][r][o][c][e][s][s][m][e][m][o][r][y]")
            AND (
                match(ScriptBlockText, "(?i)[c][r][e][a][t][e][r][e][m][o][t][e][t][h][r][e][a][d]")
                OR
                match(ScriptBlockText, "(?i)[q][u][e][u][e][u][s][e][r][a][p][c]")
            )
        )
        OR
        (
            match(ScriptBlockText, "(?i)[o][p][e][n][t][h][r][e][a][d]")
            AND match(ScriptBlockText, "(?i)[s][u][s][p][e][n][d][t][h][r][e][a][d]")
            AND match(ScriptBlockText, "(?i)[g][e][t][t][h][r][e][a][d][c][o][n][t][e][x][t]")
            AND match(ScriptBlockText, "(?i)[w][r][i][t][e][p][r][o][c][e][s][s][m][e][m][o][r][y]")
            AND match(ScriptBlockText, "(?i)[s][e][t][t][h][r][e][a][d][c][o][n][t][e][x][t]")
            AND match(ScriptBlockText, "(?i)[r][e][s][u][m][e][t][h][r][e][a][d]")
        )
        OR
        (
            match(ScriptBlockText, "(?i)[c][r][e][a][t][e][p][r][o][c][e][s][s]")
            AND match(ScriptBlockText, "(?i)[v][i][r][t][u][a][l][a][l][l][o][c]")
            AND match(ScriptBlockText, "(?i)[w][r][i][t][e][p][r][o][c][e][s][s][m][e][m][o][r][y]")
            AND match(ScriptBlockText, "(?i)[s][e][t][t][h][r][e][a][d][c][o][n][t][e][x][t]")
            AND ScriptBlockText = "*ResumeThread*"
        )
        OR
        (
            match(ScriptBlockText, "(?i)[n][t][c][r][e][a][t][e][s][e][c][t][i][o][n]")
            AND match(ScriptBlockText, "(?i)[n][t][m][a][p][v][i][e][w][o][f][s][e][c][t][i][o][n]")
            AND match(ScriptBlockText, "(?i)[c][r][e][a][t][e][r][e][m][o][t][e][t][h][r][e][a][d]")
        )
    | fillnull
    | stats count min(_time) as firstTime
                  max(_time) as lastTime
       by dest signature signature_id user_id vendor_product EventID
          Guid Opcode Name Path ProcessID ScriptBlockId ScriptBlockText
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `powershell_pinvoke_process_injection_api_chain_filter`
how_to_implement: |-
    The following analytic requires PowerShell operational logs to be imported. Modify the powershell macro as needed to match the sourcetype or add index. This analytic is specific to 4104, or PowerShell Script Block Logging.
known_false_positives: |-
    No false positives have been identified at this time.
references:
    - https://learn.microsoft.com/en-us/dotnet/api/system.runtime.interopservices.dllimportattribute
    - https://www.ired.team/offensive-security/code-injection-process-injection
    - https://www.broadcom.com/support/security-center/protection-bulletin/vip-keylogger-spreads-via-multi-org-impersonation-campaign
    - https://attack.mitre.org/techniques/T1055/
    - https://attack.mitre.org/techniques/T1620/
finding:
    title: A PowerShell script Script block ID [$ScriptBlockId$] contains a possible P-Invoke process injection API chain via either inline Add-Type class declaration or direct static method invocation on [$dest$]
    entity:
        field: user_id
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: A PowerShell script Script block ID [$ScriptBlockId$] contains a possible P-Invoke process injection API chain via either inline Add-Type class declaration or direct static method invocation on [$dest$]
analytic_story:
    - VIP Keylogger
    - Phantom Stealer
asset_type: Endpoint
mitre_attack_id:
    - T1055.001
    - T1055.003
    - T1055.004
    - T1055.012
    - T1055.013
    - T1059.001
    - T1620
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint