Windows Suspicious React or Next.js Child Process

name: Windows Suspicious React or Next.js Child Process
id: baa80bc8-7c9c-4395-b458-b69feb92830a
version: 5
creation_date: '2025-12-08'
modification_date: '2026-05-13'
author: Nasreddine Bencherchali, Splunk
status: production
type: TTP
description: |
    This analytic detects Windows processes such as cmd.exe, PowerShell, and common Windows LOLBINs being spawned by React or Next.js application servers.
    In the context of CVE-2025-55182 / React2Shell / CVE-2025-66478 for Next.js, successful exploitation can lead to arbitrary JavaScript execution on the server, which in turn is used to invoke Node's child_process APIs (for example child_process.execSync) to run OS-level commands.
    This detection focuses on suspicious child processes where a Next/React server process spawns an uncommon process.
    Such activity might be a strong indicator of exploitation of the aforementioned vulnerability.
data_source:
    - Sysmon EventID 1
    - CrowdStrike ProcessRollup2
search: |
    | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime
      from datamodel=Endpoint.Processes
      where
        Processes.parent_process_name = "node.exe"
        Processes.parent_process IN (
          "*--experimental-https*",
          "*--experimental-next-config-strip-types*",
          "*\\node_modules\\next*",
          "*next dev*",
          "*next start*",
          "*next\" start*",
          "*node_modules\\.bin\\\\..\\next*",
          "*react-scripts start*",
          "*start-server.js*",
        )
        AND
        (
          Processes.process_name IN (
            "bash.exe",
            "bitsadmin.exe",
            "calc.exe",
            "CalculatorApp.exe",
            "certutil.exe",
            "cscript.exe",
            "curl.exe",
            "ftp.exe",
            "ipconfig.exe",
            "mshta.exe",
            "netstat.exe",
            "OpenConsole.exe",
            "powershell.exe",
            "pwsh.exe",
            "regsvr32.exe",
            "rundll32.exe",
            "sh.exe",
            "tftp.exe",
            "wget.exe",
            "win32calc.exe",
            "wmic.exe",
            "wscript.exe",
            "wsl.exe",
            "wt.exe"
          )
          OR
          (
            Processes.process_name = "cmd.exe"
            AND NOT Processes.process = "*/d /s /c *"
          )
          OR
          (
            Processes.process_name = "cmd.exe"
            Processes.process = "*/d /s /c *"
            AND NOT (
              Processes.process = "*git config --local --get remote.origin.url*"
              OR
              (
                Processes.process = "*netstat -ano | findstr /C:*"
                Processes.process = "* | findstr LISTENING*"
              )
              OR
              (
                Processes.parent_process = "*--experimental-https*"
                Processes.process = "*\\mkcert\\*"
                Processes.process IN ("* -CAROOT*", "* -install *")
              )
            )
          )
        )
    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)`
    | `windows_suspicious_react_or_next_js_child_process_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: |
    Rare false positives might show up from child processes such as cmd or powershell. Apply additional filters as needed.
references:
    - https://react.dev/blog/2025/12/03/critical-security-vulnerability-in-react-server-components
    - https://nextjs.org/blog/CVE-2025-66478
    - https://nvd.nist.gov/vuln/detail/CVE-2025-55182
    - https://gist.github.com/maple3142/48bc9393f45e068cf8c90ab865c0f5f3
    - https://www.wiz.io/blog/critical-vulnerability-in-react-cve-2025-55182
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | 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: 7d
      latest_offset: "0"
finding:
    title: A Node-based server process ($parent_process_name$) spawned the child process $process_name$ with command-line $process$ on host $dest$ by user $user$, which may indicate remote code execution via React Server Components (CVE-2025-55182 / React2Shell) or abuse of a similar Node.js RCE vector.
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: A Node-based server process ($parent_process_name$) spawned the child process $process_name$ with command-line $process$ on host $dest$ by user $user$, which may indicate remote code execution via React Server Components (CVE-2025-55182 / React2Shell) or abuse of a similar Node.js RCE vector.
threat_objects:
    - field: parent_process_name
      type: process
    - field: process
      type: process
    - field: process_name
      type: process
analytic_story:
    - React2Shell
asset_type: Endpoint
mitre_attack_id:
    - T1190
    - T1059.003
    - T1059.001
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/emerging_threats/react2shell/react2shell_windows.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit