{
  "author": "_ext-sigma-7a14fbc3-54d9-4b4d-8700-61eddada04f0[bulk][segment]",
  "cat": "Non Interactive PowerShell Process Spawned",
  "detect": {
    "event": {
      "BASE_ADDRESS": 9764864,
      "COMMAND_LINE": "\"C:\\Windows\\SysWOW64\\WindowsPowerShell\\v1.0\\powershell.exe\" -NoLogo -NonInteractive -NoProfile -ExecutionPolicy Bypass (Get-Item \u0027C:\\Program Files (x86)\\Google\\Chrome Remote Desktop\\CurrentVersion\u0027).Delete()",
      "FILE_IS_SIGNED": 1,
      "FILE_PATH": "C:\\Windows\\SysWOW64\\WindowsPowerShell\\v1.0\\powershell.exe",
      "HASH": "3bfedaaa40d9e19e45a3ee10c0f14b1750b01619ebb9f39be3865bcfdacdd2e5",
      "MEMORY_USAGE": 49205248,
      "PARENT": {
        "BASE_ADDRESS": 14942208,
        "COMMAND_LINE": "C:\\Windows\\syswow64\\MsiExec.exe -Embedding 57917046E265CB85396AB79820287388 E Global\\MSI0000",
        "FILE_IS_SIGNED": 1,
        "FILE_PATH": "C:\\Windows\\syswow64\\MsiExec.exe",
        "HASH": "34e2e75cb8622809e4f95b3e665071d755870f503167268f23d0110cc5f7ee2c",
        "MEMORY_USAGE": 13615104,
        "PARENT_ATOM": "23a7a08840c587c857088e4669c19e54",
        "PARENT_PROCESS_ID": 26224,
        "PROCESS_ID": 32732,
        "THIS_ATOM": "0077d031151f6ea2ed35db9269c19e54",
        "THREADS": 7,
        "TIMESTAMP": 1774296660033,
        "USER_NAME": "NT AUTHORITY\\SYSTEM"
      },
      "PARENT_PROCESS_ID": 32732,
      "PROCESS_ID": 35828,
      "THREADS": 25,
      "USER_NAME": "NT AUTHORITY\\SYSTEM"
    },
    "routing": {
      "arch": 2,
      "did": "",
      "event_id": "9fa51a59-54b7-4b2c-ab6c-a324ebcbe294",
      "event_time": 1774296670971,
      "event_type": "NEW_PROCESS",
      "ext_ip": "23.128.32.10",
      "hostname": "desktop-atsepsk",
      "iid": "b2cd59fc-d09d-49e0-a9f2-1fd79ee9c175",
      "int_ip": "192.168.50.200",
      "latency": -284,
      "moduleid": 2,
      "oid": "d3541070-8b0e-4663-8a6a-aa0727aacd36",
      "parent": "0077d031151f6ea2ed35db9269c19e54",
      "plat": 268435456,
      "sid": "8f3a47be-5629-4c66-921d-17c39ed07e87",
      "tags": [
        "fusion-soc-alert",
        "fusion-soc-case",
        "fusion-soc-pulled",
        "fusion-soc-triage",
        "fusionsoc-critical",
        "fusionsoc-high",
        "fusionsoc-investigated",
        "joys",
        "windows",
        "yara_detection_memory",
        "yara_detection_disk"
      ],
      "this": "9518d3fccae24725ea4e9dde69c19e5f"
    }
  },
  "detect_id": "bdf3fbdf-b43b-4ce8-9e21-e07969c19e5e",
  "detect_mtd": {
    "author": "Roberto Rodriguez @Cyb3rWard0g (rule), oscd.community (improvements)",
    "description": "Detects non-interactive PowerShell activity by looking at the \"powershell\" process with a non-user GUI process such as \"explorer.exe\" as a parent.",
    "falsepositives": [
      "Likely. Many admin scripts and tools leverage PowerShell in their BAT or VB scripts which may trigger this rule often. It is best to add additional filters or use this to hunt for anomalies"
    ],
    "level": "low",
    "references": [
      "https://web.archive.org/web/20200925032237/https://threathunterplaybook.com/notebooks/windows/02_execution/WIN-190410151110.html"
    ],
    "tags": [
      "attack.execution",
      "attack.t1059.001"
    ]
  },
  "gen_time": 1774296670749,
  "link": "https://app.limacharlie.io/orgs/d3541070-8b0e-4663-8a6a-aa0727aacd36/sensors/8f3a47be-5629-4c66-921d-17c39ed07e87/timeline?time=1774296670\u0026selected=9518d3fccae24725ea4e9dde69c19e5f",
  "namespace": "general",
  "routing": {
    "arch": 2,
    "did": "",
    "event_id": "9fa51a59-54b7-4b2c-ab6c-a324ebcbe294",
    "event_time": 1774296670971,
    "event_type": "NEW_PROCESS",
    "ext_ip": "23.128.32.10",
    "hostname": "desktop-atsepsk",
    "iid": "b2cd59fc-d09d-49e0-a9f2-1fd79ee9c175",
    "int_ip": "192.168.50.200",
    "latency": -284,
    "moduleid": 2,
    "oid": "d3541070-8b0e-4663-8a6a-aa0727aacd36",
    "parent": "0077d031151f6ea2ed35db9269c19e54",
    "plat": 268435456,
    "sid": "8f3a47be-5629-4c66-921d-17c39ed07e87",
    "tags": [
      "fusion-soc-alert",
      "fusion-soc-case",
      "fusion-soc-pulled",
      "fusion-soc-triage",
      "fusionsoc-critical",
      "fusionsoc-high",
      "fusionsoc-investigated",
      "joys",
      "windows",
      "yara_detection_memory",
      "yara_detection_disk"
    ],
    "this": "9518d3fccae24725ea4e9dde69c19e5f"
  },
  "rule_tags": [
    "ext:ext-sigma",
    "attack.execution",
    "attack.t1059.001"
  ],
  "source": "d3541070-8b0e-4663-8a6a-aa0727aacd36.b2cd59fc-d09d-49e0-a9f2-1fd79ee9c175.8f3a47be-5629-4c66-921d-17c39ed07e87.10000000.2",
  "source_rule": "service.windows_process_creation/proc_creation_win_powershell_non_interactive_execution",
  "ts": 1774296671000
}

{
  "virustotal": {
    "malicious": false,
    "provider": "virustotal",
    "reputation": 0,
    "stats": {
      "confirmed-timeout": 0,
      "failure": 0,
      "harmless": 0,
      "malicious": 0,
      "suspicious": 0,
      "timeout": 11,
      "type-unsupported": 4,
      "undetected": 61
    }
  }
}

{
  "confidence": 0.933,
  "false_positive_reason": "Legitimate software maintenance via Windows Installer (MsiExec)",
  "investigation_questions": [
    "Is Chrome Remote Desktop being updated or uninstalled on this host?"
  ],
  "ioc_analysis": "The process powershell.exe and its parent MsiExec.exe are both signed binaries running from their standard Windows system directories (SysWOW64). The target file path in Program Files (x86) is a known-good location for Chrome Remote Desktop.",
  "iocs_extracted": [
    "C:\\Windows\\SysWOW64\\WindowsPowerShell\\v1.0\\powershell.exe",
    "C:\\Windows\\syswow64\\MsiExec.exe",
    "C:\\Program Files (x86)\\Google\\Chrome Remote Desktop\\CurrentVersion"
  ],
  "mitre_techniques": [
    "T1059.001"
  ],
  "recommended_actions": [
    "Close case as false positive (unanimous AI verdict)",
    "No action required",
    "Consider adding an exclusion for MsiExec spawning PowerShell to clean up Chrome Remote Desktop directories to reduce noise."
  ],
  "risk_score": 13,
  "severity": "low",
  "summary": "**Vote: UNANIMOUS (3/3 -\u003e FALSE POSITIVE)**\n\n### \u264a gemini-cli Analysis (Primary)\n**Verdict:** false_positive | **Confidence:** 0.95\nThis detection is a false positive triggered by a legitimate Windows Installer (MsiExec) process performing maintenance on Google Chrome Remote Desktop. The PowerShell command is used to delete a directory during an installation or update, which is standard behavior for MsiExec when running as SYSTEM.\n\n**IOC Analysis:** The process powershell.exe and its parent MsiExec.exe are both signed binaries running from their standard Windows system directories (SysWOW64). The target file path in Program Files (x86) is a known-good location for Chrome Remote Desktop.\n\n---\n\n### \ud83e\udd16 qwen3.5:4b Analysis (Secondary)\n**Verdict:** false_positive | **Confidence:** 0.95\nThis detection is a false positive because the PowerShell process was spawned by Microsoft Installer (msiexec.exe) running under SYSTEM context to perform legitimate system maintenance or software installation tasks. The command line indicates deletion of a Google Chrome Remote Desktop file, which is consistent with normal application behavior.\n\n**IOC Analysis:** The PowerShell executable is located in its expected Windows directory (SysWOW64), is Microsoft-signed (FILE_IS_SIGNED: 1), and has a known-good hash. The parent process msiexec.exe is also legitimate and running from System32. The command deletes a file associated with Google Chrome Remote Desktop, which is not inherently malicious.\n\n---\n\n### \ud83e\udd16 deepseek-r1:8b Analysis (Secondary)\n**Verdict:** false_positive | **Confidence:** 0.9\nThe detection flagged a PowerShell process spawn, but it was initiated by MsiExec.exe, a legitimate system process, and the command appears to be part of a normal uninstallation routine for Chrome Remote Desktop. Given the benign context and historical false positive data, this is likely not malicious.\n\n**IOC Analysis:** The FILE_PATH C:\\Windows\\SysWOW64\\WindowsPowerShell\\v1.0\\powershell.exe is a legitimate Microsoft binary location. The HASH is Microsoft-signed, confirming its authenticity. The command line action targets a known legitimate application directory, suggesting it\u0027s part of a standard process uninstallation, not malicious activity.",
  "verdict": "false_positive",
  "voting": {
    "auto_action": "auto_close_fp",
    "mode": "unanimous",
    "total_models": 3,
    "vote_summary": [
      "gemini-cli: false_positive (low, 95% confidence)",
      "qwen3.5:4b: false_positive (low, 95% confidence)",
      "deepseek-r1:8b: false_positive (low, 90% confidence)"
    ],
    "votes": [
      {
        "confidence": 0.95,
        "model": "gemini-cli",
        "verdict": "false_positive"
      },
      {
        "confidence": 0.95,
        "model": "qwen3.5:4b",
        "verdict": "false_positive"
      },
      {
        "confidence": 0.9,
        "model": "deepseek-r1:8b",
        "verdict": "false_positive"
      }
    ],
    "winning_count": 3,
    "winning_verdict": "false_positive"
  }
}