{
  "author": "_ext-sigma-7a14fbc3-54d9-4b4d-8700-61eddada04f0[bulk][segment]",
  "cat": "Directory Removal Via Rmdir",
  "detect": {
    "event": {
      "COMMAND_LINE": "\"C:\\Windows\\System32\\cmd.exe\" /q /c rmdir /s /q \"C:\\Users\\pjhow\\AppData\\Local\\Microsoft\\OneDrive\\26.022.0203.0006\"",
      "FILE_IS_SIGNED": 1,
      "FILE_PATH": "C:\\Windows\\System32\\cmd.exe",
      "HASH": "f682aadda9deb654885ae17909380a25f7cb1a43ac0934ac425ee8de4924c7f3",
      "MEMORY_USAGE": 36864,
      "PARENT": {
        "BASE_ADDRESS": 140697881149440,
        "COMMAND_LINE": "C:\\WINDOWS\\Explorer.EXE",
        "FILE_IS_SIGNED": 1,
        "FILE_PATH": "C:\\WINDOWS\\Explorer.EXE",
        "HASH": "6d560ce5e75149dffe1b67f0a9f1a0717c9996d50ef2dbf3349b251b64c3a195",
        "MEMORY_USAGE": 34713600,
        "PARENT_ATOM": "b4c888978aa0174f6ca942a969c30db5",
        "PARENT_PROCESS_ID": 3324,
        "PROCESS_ID": 1984,
        "THIS_ATOM": "95030fcbb1b0f80539943cfe69c30db5",
        "THREADS": 11,
        "TIMESTAMP": 1774390708232,
        "USER_NAME": "WIN-91LCCQ536B4\\pjhow"
      },
      "PARENT_PROCESS_ID": 1984,
      "PROCESS_ID": 8592,
      "USER_NAME": "WIN-91LCCQ536B4\\pjhow"
    },
    "routing": {
      "arch": 2,
      "did": "",
      "event_id": "7b5e9852-0c65-4dd3-ab73-6299fbff39f5",
      "event_time": 1774390753776,
      "event_type": "NEW_PROCESS",
      "ext_ip": "23.128.32.10",
      "hostname": "win-91lccq536b4",
      "iid": "b2cd59fc-d09d-49e0-a9f2-1fd79ee9c175",
      "int_ip": "192.168.50.170",
      "latency": 1706,
      "moduleid": 2,
      "oid": "d3541070-8b0e-4663-8a6a-aa0727aacd36",
      "parent": "95030fcbb1b0f80539943cfe69c30db5",
      "plat": 268435456,
      "sid": "f8e98d83-79d8-4ff7-9fe1-7c507dad89e4",
      "tags": [
        "frontdesk",
        "fusion-soc-alert",
        "fusion-soc-case",
        "fusion-soc-pulled",
        "fusion-soc-triage",
        "fusionsoc-critical",
        "fusionsoc-investigated",
        "windows",
        "yara_detection_memory"
      ],
      "this": "b40b4fffe58781978d2793c669c30de3"
    }
  },
  "detect_id": "f7283c55-1210-486d-8360-53fa69c30de3",
  "detect_mtd": {
    "author": "frack113",
    "description": "Detects execution of the builtin \"rmdir\" command in order to delete directories.\nAdversaries may delete files left behind by the actions of their intrusion activity.\nMalware, tools, or other non-native files dropped or created on a system by an adversary may leave traces to indicate to what was done within a network and how.\nRemoval of these files can occur during an intrusion, or as part of a post-intrusion process to minimize the adversary\u0027s footprint.\n",
    "falsepositives": [
      "Unknown"
    ],
    "level": "low",
    "references": [
      "https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1070.004/T1070.004.md",
      "https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/erase"
    ],
    "tags": [
      "attack.defense-evasion",
      "attack.t1070.004"
    ]
  },
  "gen_time": 1774390755484,
  "link": "https://app.limacharlie.io/orgs/d3541070-8b0e-4663-8a6a-aa0727aacd36/sensors/f8e98d83-79d8-4ff7-9fe1-7c507dad89e4/timeline?time=1774390753\u0026selected=b40b4fffe58781978d2793c669c30de3",
  "namespace": "general",
  "routing": {
    "arch": 2,
    "did": "",
    "event_id": "7b5e9852-0c65-4dd3-ab73-6299fbff39f5",
    "event_time": 1774390753776,
    "event_type": "NEW_PROCESS",
    "ext_ip": "23.128.32.10",
    "hostname": "win-91lccq536b4",
    "iid": "b2cd59fc-d09d-49e0-a9f2-1fd79ee9c175",
    "int_ip": "192.168.50.170",
    "latency": 1706,
    "moduleid": 2,
    "oid": "d3541070-8b0e-4663-8a6a-aa0727aacd36",
    "parent": "95030fcbb1b0f80539943cfe69c30db5",
    "plat": 268435456,
    "sid": "f8e98d83-79d8-4ff7-9fe1-7c507dad89e4",
    "tags": [
      "frontdesk",
      "fusion-soc-alert",
      "fusion-soc-case",
      "fusion-soc-pulled",
      "fusion-soc-triage",
      "fusionsoc-critical",
      "fusionsoc-investigated",
      "windows",
      "yara_detection_memory"
    ],
    "this": "b40b4fffe58781978d2793c669c30de3"
  },
  "rule_tags": [
    "ext:ext-sigma",
    "attack.defense-evasion",
    "attack.t1070.004"
  ],
  "source": "d3541070-8b0e-4663-8a6a-aa0727aacd36.b2cd59fc-d09d-49e0-a9f2-1fd79ee9c175.f8e98d83-79d8-4ff7-9fe1-7c507dad89e4.10000000.2",
  "source_rule": "service.windows_process_creation/proc_creation_win_cmd_rmdir_execution",
  "ts": 1774390755000
}

{
  "virustotal": {
    "malicious": false,
    "provider": "virustotal",
    "reputation": 1,
    "stats": {
      "confirmed-timeout": 0,
      "failure": 0,
      "harmless": 0,
      "malicious": 0,
      "suspicious": 0,
      "timeout": 0,
      "type-unsupported": 4,
      "undetected": 72
    }
  }
}

{
  "confidence": 0.95,
  "false_positive_reason": "Legitimate software maintenance (OneDrive update/cleanup)",
  "investigation_questions": [
    "Is this specific OneDrive version (26.022.0203.0006) associated with a recent update?"
  ],
  "ioc_analysis": "The process \u0027cmd.exe\u0027 (f682aadda9deb654885ae17909380a25f7cb1a43ac0934ac425ee8de4924c7f3) is a known legitimate Microsoft binary with 0 detections on VirusTotal. The parent process \u0027Explorer.EXE\u0027 is also a signed Microsoft binary running from the expected directory.",
  "iocs_extracted": [
    "f682aadda9deb654885ae17909380a25f7cb1a43ac0934ac425ee8de4924c7f3",
    "6d560ce5e75149dffe1b67f0a9f1a0717c9996d50ef2dbf3349b251b64c3a195",
    "C:\\Users\\pjhow\\AppData\\Local\\Microsoft\\OneDrive\\26.022.0203.0006"
  ],
  "mitre_techniques": [
    "T1070.004"
  ],
  "recommended_actions": [
    "Close case as false positive (unanimous AI verdict)",
    "Whitelists this specific OneDrive cleanup pattern to reduce future false positive alerts.",
    "Close the case as a false positive."
  ],
  "risk_score": 8,
  "severity": "low",
  "summary": "**Vote: UNANIMOUS (3/3 -\u003e FALSE POSITIVE)**\n\n### \u264a gemini-cli Analysis (Primary)\n**Verdict:** false_positive | **Confidence:** 1.0\nThe detection flagged a \u0027rmdir\u0027 command deleting a OneDrive version directory (\u002726.022.0203.0006\u0027) within the user\u0027s local AppData folder. This is standard behavior for OneDrive during updates or maintenance where old version directories are cleaned up silently.\n\n**IOC Analysis:** The process \u0027cmd.exe\u0027 (f682aadda9deb654885ae17909380a25f7cb1a43ac0934ac425ee8de4924c7f3) is a known legitimate Microsoft binary with 0 detections on VirusTotal. The parent process \u0027Explorer.EXE\u0027 is also a signed Microsoft binary running from the expected directory.\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 cmd.exe is a legitimate Windows system binary running from its expected location (System32) and is signed by Microsoft. The command removes a OneDrive cache directory, which is a common administrative or user maintenance task.\n\n**IOC Analysis:** The process is cmd.exe located in C:\\Windows\\System32\\, which is the known-good location for this binary. The file hash matches the official Microsoft signature and FILE_IS_SIGNED is true. The parent chain (Explorer -\u003e unknown service) suggests normal system activity rather than malicious execution.\n\n---\n\n### \ud83e\udd16 deepseek-r1:8b Analysis (Secondary)\n**Verdict:** false_positive | **Confidence:** 0.9\nThe detection involves a legitimate cmd.exe process running from C:\\Windows\\System32, which is a known system binary. The command deletes a user\u0027s OneDrive directory, likely due to user action or a benign process, making this detection a false positive.\n\n**IOC Analysis:** FILE_PATH C:\\Windows\\System32\\cmd.exe is a legitimate Windows system binary located in the expected directory. The HASH is signed, indicating it is likely Microsoft-signed and not malicious. FILE_IS_SIGNED is true, supporting its legitimacy. The parent process Explorer.EXE is also legitimate, and the action of deleting a user directory is common and not inherently malicious.",
  "verdict": "false_positive",
  "voting": {
    "auto_action": "auto_close_fp",
    "mode": "unanimous",
    "total_models": 3,
    "vote_summary": [
      "gemini-cli: false_positive (low, 100% confidence)",
      "qwen3.5:4b: false_positive (low, 95% confidence)",
      "deepseek-r1:8b: false_positive (low, 90% confidence)"
    ],
    "votes": [
      {
        "confidence": 1.0,
        "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"
  }
}