{
  "author": "_ext-sigma-7a14fbc3-54d9-4b4d-8700-61eddada04f0[bulk][segment]",
  "cat": "Potentially Suspicious Cabinet File Expansion",
  "detect": {
    "event": {
      "COMMAND_LINE": "\"C:\\WINDOWS\\SysWOW64\\expand.exe\" -r -F:* \"C:\\ProgramData\\Dell\\SupportAssist\\TechnicianToolkit\\Library\\UpdateFiles.cab\" \"C:\\ProgramData\\Dell\\SupportAssist\\SRE\\LocalDB\\Update\"",
      "FILE_IS_SIGNED": 1,
      "FILE_PATH": "C:\\WINDOWS\\SysWOW64\\expand.exe",
      "HASH": "dfc1709a2988301f7a9d145fb107793e3299ecc85f4b9702523939e35573ab85",
      "PARENT": {
        "BASE_ADDRESS": 9633792,
        "COMMAND_LINE": "\"C:\\Program Files\\Dell\\SupportAssistAgent\\SRE\\SRE.exe\" \"en\" \"C:\\ProgramData\\Dell\\SupportAssist\\Agent\\Certificate\\SRE\\e231b57f-d97f-475d-bd70-e5b839232e92.pfx\" \"127.0.0.1:10528\" \"5ce2f89a-f6dd-497e-a5d6-38e955aaf176\" \"false\"",
        "FILE_IS_SIGNED": 1,
        "FILE_PATH": "C:\\Program Files\\Dell\\SupportAssistAgent\\SRE\\SRE.exe",
        "HASH": "4209038199a68a376fc84137887a18bbeb149f54ad610645f2d585c44a569f31",
        "MEMORY_USAGE": 4648960,
        "PARENT_ATOM": "7a1843f3f92f80d78b404bd469bb9681",
        "PARENT_PROCESS_ID": 12556,
        "PROCESS_ID": 9256,
        "THIS_ATOM": "6b4a9782c9cf20e12a85883e69bb96e1",
        "THREADS": 4,
        "TIMESTAMP": 1773901536063,
        "USER_NAME": "NT AUTHORITY\\SYSTEM"
      },
      "PARENT_PROCESS_ID": 9256,
      "PROCESS_ID": 12368
    },
    "routing": {
      "arch": 2,
      "did": "",
      "event_id": "0f22c092-d911-4dd7-833c-adb7010d37fb",
      "event_time": 1773901556902,
      "event_type": "NEW_PROCESS",
      "ext_ip": "23.128.32.10",
      "hostname": "desktop-3nfb237",
      "iid": "b2cd59fc-d09d-49e0-a9f2-1fd79ee9c175",
      "int_ip": "192.168.50.40",
      "latency": 645,
      "moduleid": 2,
      "oid": "d3541070-8b0e-4663-8a6a-aa0727aacd36",
      "parent": "6b4a9782c9cf20e12a85883e69bb96e1",
      "plat": 268435456,
      "sid": "ed8f7c3f-3a1a-493e-8fa4-35eb8c30b136",
      "tags": [
        "fusion-soc-alert",
        "fusion-soc-case",
        "fusion-soc-pulled",
        "fusion-soc-triage",
        "fusionsoc-critical",
        "fusionsoc-high",
        "fusionsoc-investigated",
        "qucikbooks",
        "windows",
        "yara_detection_memory"
      ],
      "this": "59d98d389092d2008b6eaf6369bb96f5"
    }
  },
  "detect_id": "2d874dc2-1bca-436c-af4f-108669bb96f5",
  "detect_mtd": {
    "author": "Bhabesh Raj, X__Junior (Nextron Systems)",
    "description": "Detects the expansion or decompression of cabinet files from potentially suspicious or uncommon locations, e.g. seen in Iranian MeteorExpress related attacks",
    "falsepositives": [
      "System administrator Usage"
    ],
    "level": "medium",
    "references": [
      "https://labs.sentinelone.com/meteorexpress-mysterious-wiper-paralyzes-iranian-trains-with-epic-troll",
      "https://blog.malwarebytes.com/threat-intelligence/2021/08/new-variant-of-konni-malware-used-in-campaign-targetting-russia/"
    ],
    "tags": [
      "attack.defense-evasion",
      "attack.t1218"
    ]
  },
  "gen_time": 1773901557556,
  "link": "https://app.limacharlie.io/orgs/d3541070-8b0e-4663-8a6a-aa0727aacd36/sensors/ed8f7c3f-3a1a-493e-8fa4-35eb8c30b136/timeline?time=1773901556\u0026selected=59d98d389092d2008b6eaf6369bb96f5",
  "namespace": "general",
  "routing": {
    "arch": 2,
    "did": "",
    "event_id": "0f22c092-d911-4dd7-833c-adb7010d37fb",
    "event_time": 1773901556902,
    "event_type": "NEW_PROCESS",
    "ext_ip": "23.128.32.10",
    "hostname": "desktop-3nfb237",
    "iid": "b2cd59fc-d09d-49e0-a9f2-1fd79ee9c175",
    "int_ip": "192.168.50.40",
    "latency": 645,
    "moduleid": 2,
    "oid": "d3541070-8b0e-4663-8a6a-aa0727aacd36",
    "parent": "6b4a9782c9cf20e12a85883e69bb96e1",
    "plat": 268435456,
    "sid": "ed8f7c3f-3a1a-493e-8fa4-35eb8c30b136",
    "tags": [
      "fusion-soc-alert",
      "fusion-soc-case",
      "fusion-soc-pulled",
      "fusion-soc-triage",
      "fusionsoc-critical",
      "fusionsoc-high",
      "fusionsoc-investigated",
      "qucikbooks",
      "windows",
      "yara_detection_memory"
    ],
    "this": "59d98d389092d2008b6eaf6369bb96f5"
  },
  "rule_tags": [
    "ext:ext-sigma",
    "attack.defense-evasion",
    "attack.t1218"
  ],
  "source": "d3541070-8b0e-4663-8a6a-aa0727aacd36.b2cd59fc-d09d-49e0-a9f2-1fd79ee9c175.ed8f7c3f-3a1a-493e-8fa4-35eb8c30b136.10000000.2",
  "source_rule": "service.windows_process_creation/proc_creation_win_expand_cabinet_files",
  "ts": 1773901557000
}

{
  "virustotal": {
    "malicious": false,
    "provider": "virustotal",
    "reputation": -11,
    "stats": {
      "confirmed-timeout": 0,
      "failure": 7,
      "harmless": 0,
      "malicious": 0,
      "suspicious": 0,
      "timeout": 2,
      "type-unsupported": 4,
      "undetected": 63
    }
  }
}

{
  "confidence": 0.943,
  "false_positive_reason": "Legitimate software update/maintenance (Dell SupportAssist)",
  "investigation_questions": [
    "Does this specific SRE.exe hash appear across other Dell-managed assets in the environment?"
  ],
  "ioc_analysis": "The process expand.exe is a signed Microsoft binary located in the expected C:\\Windows\\SysWOW64\\ directory. The parent process SRE.exe is a signed Dell binary located in the standard Program Files directory. Both the source .cab file and the destination update directory are within the legitimate Dell SupportAssist ProgramData path.",
  "iocs_extracted": [
    "C:\\WINDOWS\\SysWOW64\\expand.exe",
    "C:\\Program Files\\Dell\\SupportAssistAgent\\SRE\\SRE.exe",
    "dfc1709a2988301f7a9d145fb107793e3299ecc85f4b9702523939e35573ab85",
    "4209038199a68a376fc84137887a18bbeb149f54ad610645f2d585c44a569f31"
  ],
  "mitre_techniques": [
    "T1140"
  ],
  "recommended_actions": [
    "Close case as false positive (unanimous AI verdict)",
    "No action required as this is legitimate maintenance activity.",
    "Consider tuning the detection rule to exclude expand.exe when spawned by signed Dell SupportAssist binaries."
  ],
  "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:** 0.98\nThe event depicts the legitimate Windows utility expand.exe being utilized by the Dell SupportAssistAgent (SRE.exe) to extract update files from a cabinet archive. This is a routine application maintenance and update procedure consistent with Dell SupportAssist operations.\n\n**IOC Analysis:** The process expand.exe is a signed Microsoft binary located in the expected C:\\Windows\\SysWOW64\\ directory. The parent process SRE.exe is a signed Dell binary located in the standard Program Files directory. Both the source .cab file and the destination update directory are within the legitimate Dell SupportAssist ProgramData path.\n\n---\n\n### \ud83e\udd16 qwen3.5:4b Analysis (Secondary)\n**Verdict:** false_positive | **Confidence:** 0.95\nThe detection flagged a legitimate Windows system binary (expand.exe) running from its expected SysWOW64 directory to expand a Dell SupportAssist CAB file. Historical analyst feedback consistently marks similar events as false positives or benign.\n\n**IOC Analysis:** The process is a known Microsoft-signed Windows system utility located in C:\\WINDOWS\\SysWOW64\\, which is the correct location for 32-bit system binaries. The command line shows it expanding a CAB file associated with Dell SupportAssist software, a legitimate enterprise management tool. The parent process chain (SRE.exe -\u003e SRE.exe) indicates this is part of standard support assistant maintenance operations.\n\n---\n\n### \ud83e\udd16 deepseek-r1:8b Analysis (Secondary)\n**Verdict:** false_positive | **Confidence:** 0.9\nThe detection event involves the creation of a process using expand.exe, a standard Windows utility for cabinet file expansion, located in the SysWOW64 directory. Given the context of the parent process from Dell SupportAssist and the signed nature of the file, this activity is likely part of a legitimate software update process.\n\n**IOC Analysis:** FILE_PATH: C:\\WINDOWS\\SysWOW64\\expand.exe is a known Windows system binary for expanding cabinet files, running from its expected directory, making it likely benign. HASH: dfc1709a2988301f7a9d145fb107793e3299ecc85f4b9702523939e35573ab85 is a hash of a signed file, which aligns with legitimate system binaries. FILE_IS_SIGNED: 1 confirms the file is signed, reducing the likelihood of malware. The command line shows expansion of a cabinet file for Dell SupportAssist, a legitimate software suite, further supporting benign intent.",
  "verdict": "false_positive",
  "voting": {
    "auto_action": "auto_close_fp",
    "mode": "unanimous",
    "total_models": 3,
    "vote_summary": [
      "gemini-cli: false_positive (low, 98% confidence)",
      "qwen3.5:4b: false_positive (low, 95% confidence)",
      "deepseek-r1:8b: false_positive (low, 90% confidence)"
    ],
    "votes": [
      {
        "confidence": 0.98,
        "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"
  }
}