{
  "author": "_ext-sigma-7a14fbc3-54d9-4b4d-8700-61eddada04f0[bulk][segment]",
  "cat": "Potentially Suspicious Cabinet File Expansion",
  "detect": {
    "event": {
      "BASE_ADDRESS": 3276800,
      "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": 3190784,
      "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": 15436,
      "THREADS": 1,
      "USER_NAME": "NT AUTHORITY\\SYSTEM"
    },
    "routing": {
      "arch": 2,
      "did": "",
      "event_id": "23cf8f5d-ada1-4738-bf99-1fa2e6fbdda2",
      "event_time": 1773901552309,
      "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": 137,
      "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": "c1a0da329a482b4831a575c769bb96f0"
    }
  },
  "detect_id": "52f1ccf1-f8f0-43c9-8a4e-c48069bb96f0",
  "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": 1773901552448,
  "link": "https://app.limacharlie.io/orgs/d3541070-8b0e-4663-8a6a-aa0727aacd36/sensors/ed8f7c3f-3a1a-493e-8fa4-35eb8c30b136/timeline?time=1773901552\u0026selected=c1a0da329a482b4831a575c769bb96f0",
  "namespace": "general",
  "routing": {
    "arch": 2,
    "did": "",
    "event_id": "23cf8f5d-ada1-4738-bf99-1fa2e6fbdda2",
    "event_time": 1773901552309,
    "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": 137,
    "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": "c1a0da329a482b4831a575c769bb96f0"
  },
  "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": 1773901552000
}

{
  "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": 0.95,
  "false_positive_reason": "Legitimate administrative activity by OEM support software (Dell SupportAssist) performing standard updates or maintenance.",
  "investigation_questions": [
    "Is Dell SupportAssist a standard authorized tool in this environment?"
  ],
  "ioc_analysis": "C:\\WINDOWS\\SysWOW64\\expand.exe is a legitimate Windows system binary. The parent process C:\\Program Files\\Dell\\SupportAssistAgent\\SRE\\SRE.exe is a signed Dell SupportAssist component. The file being expanded (index.cab) is located within the Dell ProgramData directory, which is consistent with legitimate OEM software behavior.",
  "iocs_extracted": [
    "C:\\WINDOWS\\SysWOW64\\expand.exe",
    "dfc1709a2988301f7a9d145fb107793e3299ecc85f4b9702523939e35573ab85",
    "C:\\Program Files\\Dell\\SupportAssistAgent\\SRE\\SRE.exe",
    "4209038199a68a376fc84137887a18bbeb149f54ad610645f2d585c44a569f31"
  ],
  "mitre_techniques": [
    "T1059"
  ],
  "recommended_actions": [
    "Close case as false positive (unanimous AI verdict)",
    "Whitelist the combination of Dell SupportAssist (SRE.exe) calling expand.exe for the TechnicianToolkit directory to reduce noise."
  ],
  "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 triggered on expand.exe expanding a cabinet file, which is a common administrative action. In this instance, the process was spawned by a legitimate, signed Dell SupportAssist binary (SRE.exe) targeting a Dell-specific directory in ProgramData for what appears to be a standard software update or maintenance task.\n\n**IOC Analysis:** C:\\WINDOWS\\SysWOW64\\expand.exe is a legitimate Windows system binary. The parent process C:\\Program Files\\Dell\\SupportAssistAgent\\SRE\\SRE.exe is a signed Dell SupportAssist component. The file being expanded (index.cab) is located within the Dell ProgramData directory, which is consistent with legitimate OEM software behavior.\n\n---\n\n### \ud83e\udd16 qwen3.5:4b Analysis (Secondary)\n**Verdict:** false_positive | **Confidence:** 0.95\nThis event is a false positive because expand.exe is a legitimate Windows system binary running from its expected location (SysWOW64) and is Microsoft-signed. The process was spawned by Dell SupportAssist Agent to expand a CAB file for technician toolkit installation, which is a common administrative task.\n\n**IOC Analysis:** The IOC FILE_PATH points to C:\\WINDOWS\\SysWOW64\\expand.exe, a known Windows system binary used for extracting compressed archives. The HASH matches the legitimate Microsoft-signed version of expand.exe. The process was invoked by SRE.exe (Dell SupportAssist Agent) to extract files needed for support tools, which is a benign administrative operation.\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 by a legitimate Dell SupportAssist component, which is expanding a cabinet file as part of expected system maintenance or updates, indicating benign activity.\n\n**IOC Analysis:** The FILE_PATH C:\\WINDOWS\\SysWOW64\\expand.exe is a legacy Windows tool for cabinet file expansion, not a core system binary, but it is signed and associated with a legitimate parent process (Dell SupportAssist). The command line shows standard cabinet file expansion for a known software package, and the signed hash confirms it is likely legitimate. Given the context, this is expected behavior.",
  "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 (informational, 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"
  }
}