File Download or Read to Pipe Execution

name: File Download or Read to Pipe Execution
id: 26f86252-1549-45e1-a212-eb26840e86bc
version: 3
date: '2026-03-10'
author: Michael Haag, Nasreddine Bencherchali, Splunk, DipsyTipsy
status: production
type: TTP
description: |
    The following analytic detects the use of download or file reading utilities from Windows, Linux or MacOS to download or read the contents of a file from a remote or local source and pipe it directly to a shell for execution.
    This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions.
    This activity is significant as it is commonly associated with malicious actions like coinminers and exploits such as CVE-2021-44228 in Log4j.
    If confirmed malicious, this behavior could allow attackers to execute arbitrary code, potentially leading to system compromise and unauthorized access to sensitive data.
data_source:
    - Sysmon EventID 1
    - Sysmon for Linux EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |
    | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
    as lastTime

    from datamodel=Endpoint.Processes where

    ``` This aims to cover download utilities and file reading ones ```

    Processes.process IN (
      "*.DownloadFile(*",
      "*.DownloadString(*",
      "*ASCII.GetString*",
      "*bitsadmin*",
      "*certutil*",
      "*curl*",
      "*Invoke-RestMethod*",
      "*Invoke-WebRequest*",
      "*irm*",
      "*iwr *",
      "*mshta*",
      "*wget*"
    )

    Processes.process IN ("*|*")

    (
      ``` Linux / MacOS ```
      Processes.process IN (
        "*bash*",
        "*csh*",
        "*dash*",
        "*fish*",
        "*ksh*",
        "*rbash*",
        "*tcsh*",
        "*zsh*"
      )
      OR
      ``` Because the "sh" string can overlap and is a short atom we treat it in a special case ```
      Processes.process IN (
        "*|sh"
        "* sh*"
      )
      OR
      ``` Windows ```
      Processes.process IN ("*IEX*", "*Invoke-Expression*")
    )

    by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
       Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
       Processes.parent_process_name Processes.parent_process_path Processes.process
       Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id
       Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user
       Processes.user_id Processes.vendor_product

    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `file_download_or_read_to_pipe_execution_filter`
how_to_implement: |
    The detection is based on data that originates from Endpoint Detection
    and Response (EDR) agents. These agents are designed to provide security-related
    telemetry from the endpoints where the agent is installed. To implement this search,
    you must ingest logs that contain the process GUID, process name, and parent process.
    Additionally, you must ingest complete command-line executions. These logs must
    be processed using the appropriate Splunk Technology Add-ons that are specific to
    the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint`
    data model. Use the Splunk Common Information Model (CIM) to normalize the field
    names and speed up the data modeling process.
known_false_positives: |
    False positives should be limited, however filtering may be required.
references:
    - https://gist.github.com/nathanqthai/01808c569903f41a52e7e7b575caa890
    - https://github.com/MHaggis/notes/blob/master/utilities/warp_pipe_tester.py
    - https://www.huntress.com/blog/rapid-response-critical-rce-vulnerability-is-affecting-java
    - https://www.lunasec.io/docs/blog/log4j-zero-day/
    - https://securelist.com/bad-magic-apt/109087/
drilldown_searches:
    - name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") starthoursago=168  | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
rba:
    message: An instance of $process_name$ was identified on endpoint $dest$ attempting to immediately read or download a file and run it via a shell.
    risk_objects:
        - field: user
          type: user
          score: 50
        - field: dest
          type: system
          score: 50
    threat_objects:
        - field: process_name
          type: process_name
        - field: process
          type: process_name
tags:
    analytic_story:
        - Compromised Windows Host
        - Ingress Tool Transfer
        - Linux Living Off The Land
        - Log4Shell CVE-2021-44228
        - NPM Supply Chain Compromise
    asset_type: Endpoint
    cve:
        - CVE-2021-44228
    mitre_attack_id:
        - T1105
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: endpoint
tests:
    - name: True Positive Test - Windows
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1105/download_to_pipe_exec/download_to_pipe_exec.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
    - name: True Positive Test - Linux
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1105/download_to_pipe_exec/download_to_pipe_exec_linux.log
          source: Syslog:Linux-Sysmon/Operational
          sourcetype: sysmon:linux