{
  "author": "_ext-sigma-7a14fbc3-54d9-4b4d-8700-61eddada04f0[bulk][segment]",
  "cat": "Potentially Suspicious Cabinet File Expansion",
  "detect": {
    "event": {
      "BASE_ADDRESS": 12648448,
      "COMMAND_LINE": "\"C:\\WINDOWS\\SysWOW64\\expand.exe\" -r -F:* \"C:\\ProgramData\\Dell\\SupportAssist\\TechnicianToolkit\\index.cab\" \"C:\\ProgramData\\Dell\\SupportAssist\\TechnicianToolkit\"",
      "FILE_IS_SIGNED": 1,
      "FILE_PATH": "C:\\WINDOWS\\SysWOW64\\expand.exe",
      "HASH": "dfc1709a2988301f7a9d145fb107793e3299ecc85f4b9702523939e35573ab85",
      "MEMORY_USAGE": 2531328,
      "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": 16044,
      "THREADS": 1,
      "USER_NAME": "NT AUTHORITY\\SYSTEM"
    },
    "routing": {
      "arch": 2,
      "did": "",
      "event_id": "6ea6ee65-0710-40c4-a513-9ed3efa03639",
      "event_time": 1773901730142,
      "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": -9,
      "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": "bb448d321ab946ed3d76ad3c69bb97a2"
    }
  },
  "detect_id": "ea51f45e-8311-43cb-8a2e-641369bb97a2",
  "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": 1773901730132,
  "link": "https://app.limacharlie.io/orgs/d3541070-8b0e-4663-8a6a-aa0727aacd36/sensors/ed8f7c3f-3a1a-493e-8fa4-35eb8c30b136/timeline?time=1773901730\u0026selected=bb448d321ab946ed3d76ad3c69bb97a2",
  "namespace": "general",
  "routing": {
    "arch": 2,
    "did": "",
    "event_id": "6ea6ee65-0710-40c4-a513-9ed3efa03639",
    "event_time": 1773901730142,
    "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": -9,
    "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": "bb448d321ab946ed3d76ad3c69bb97a2"
  },
  "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": 1773901730000
}

{
  "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 Dell SupportAssist maintenance activity expanding a toolkit cabinet file.",
  "investigation_questions": [
    "Are there any other unusual processes spawned by SRE.exe on this host?"
  ],
  "ioc_analysis": "The primary IOCs are expand.exe (C:\\WINDOWS\\SysWOW64\\expand.exe) and SRE.exe (C:\\Program Files\\Dell\\SupportAssistAgent\\SRE\\SRE.exe), both of which are legitimate signed binaries. The command line shows expansion of \u0027index.cab\u0027 within the Dell SupportAssist ProgramData directory, a standard location for technician toolkits.",
  "iocs_extracted": [
    "dfc1709a2988301f7a9d145fb107793e3299ecc85f4b9702523939e35573ab85",
    "4209038199a68a376fc84137887a18bbeb149f54ad610645f2d585c44a569f31",
    "C:\\WINDOWS\\SysWOW64\\expand.exe",
    "C:\\Program Files\\Dell\\SupportAssistAgent\\SRE\\SRE.exe"
  ],
  "mitre_techniques": [
    "T1059"
  ],
  "recommended_actions": [
    "Close case as false positive (unanimous AI verdict)",
    "Whitelists the Dell SupportAssist SRE.exe process as a legitimate parent for expand.exe",
    "No further investigation required"
  ],
  "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 detection flagged the standard Windows utility expand.exe being used by Dell SupportAssist to expand a cabinet file. Both the process and its parent (SRE.exe) are signed binaries running from their expected system and program directory locations under the SYSTEM account, which is consistent with legitimate automated maintenance activity.\n\n**IOC Analysis:** The primary IOCs are expand.exe (C:\\WINDOWS\\SysWOW64\\expand.exe) and SRE.exe (C:\\Program Files\\Dell\\SupportAssistAgent\\SRE\\SRE.exe), both of which are legitimate signed binaries. The command line shows expansion of \u0027index.cab\u0027 within the Dell SupportAssist ProgramData directory, a standard location for technician toolkits.\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 expand.exe is a legitimate Windows system binary located in the expected SysWOW64 directory and is Microsoft-signed. The process was spawned by Dell SupportAssist Agent to expand a CAB file for technician toolkit installation.\n\n**IOC Analysis:** The IOC (expand.exe) matches known-good Windows system binaries running from their EXPECTED directory (C:\\WINDOWS\\SysWOW64\\). The binary is signed and the parent process chain shows legitimate enterprise support software (Dell SupportAssist Agent) initiating the operation. This is a common false positive scenario for cabinet expansion detections.\n\n---\n\n### \ud83e\udd16 deepseek-r1:8b Analysis (Secondary)\n**Verdict:** false_positive | **Confidence:** 0.9\nThe detection event involves a process creation of expand.exe, a legitimate Windows utility for cabinet file expansion, running from the expected SysWOW64 directory. The command line indicates it\u0027s expanding a cabinet file from Dell SupportAssist, a known legitimate application. Given the signed binary and benign context, this is likely a false positive.\n\n**IOC Analysis:** FILE_PATH: C:\\WINDOWS\\SysWOW64\\expand.exe is a known legitimate Windows system binary, expected in SysWOW64 for 32-bit utilities. HASH: dfc1709a2988301f7a9d145fb107793e3299ecc85f4b9702523939e35573ab85 is a valid hash for a signed binary, consistent with Windows or vendor-signed files. FILE_IS_SIGNED: 1 confirms the binary is signed, reducing malicious intent. The command line involves expanding a cabinet file from Dell SupportAssist, which is legitimate, and the parent process is SRE.exe from Dell, further supporting benignity.",
  "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"
  }
}