Powershell Fileless Process Injection via GetProcAddress

name: Powershell Fileless Process Injection via GetProcAddress
id: a26d9db4-c883-11eb-9d75-acde48001122
version: 14
creation_date: '2021-06-09'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic detects the use of `GetProcAddress` in PowerShell script blocks, leveraging PowerShell Script Block Logging (EventCode=4104). This method captures the full command sent to PowerShell, which is then logged in Windows event logs. The presence of `GetProcAddress` is unusual for typical PowerShell scripts and often indicates malicious activity, as many attack toolkits use it to achieve code execution. If confirmed malicious, this activity could allow an attacker to execute arbitrary code, potentially leading to system compromise. Analysts should review parallel processes and the entire logged script block for further investigation.
data_source:
    - Powershell Script Block Logging 4104
search: |-
    `powershell` EventCode=4104 ScriptBlockText=*getprocaddress*
      | 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_fileless_process_injection_via_getprocaddress_filter`
how_to_implement: To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://help.splunk.com/en/security-offerings/splunk-user-behavior-analytics/get-data-in/5.4.1/add-other-data-to-splunk-uba/configure-powershell-logging-to-see-powershell-anomalies-in-splunk-uba.
known_false_positives: Limited false positives. Filter as needed.
references:
    - https://help.splunk.com/en/security-offerings/splunk-user-behavior-analytics/get-data-in/5.4.1/add-other-data-to-splunk-uba/configure-powershell-logging-to-see-powershell-anomalies-in-splunk-uba.
    - https://blog.palantir.com/tampering-with-windows-event-tracing-background-offense-and-defense-4be7ac62ac63
    - https://static1.squarespace.com/static/552092d5e4b0661088167e5c/t/59c1814829f18782e24f1fe2/1505853768977/Windows+PowerShell+Logging+Cheat+Sheet+ver+Sept+2017+v2.1.pdf
    - https://www.crowdstrike.com/blog/investigating-powershell-command-and-script-logging/
    - https://www.splunk.com/en_us/blog/security/hunting-for-malicious-powershell-using-script-block-logging.html
finding:
    title: A suspicious powershell script contains GetProcAddress API on host $dest$
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Hellcat Ransomware
    - Malicious PowerShell
    - Hermetic Wiper
    - Data Destruction
asset_type: Endpoint
mitre_attack_id:
    - T1055
    - T1059.001
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint