Qbot — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 781716e73ac749f9…

MALICIOUS

Office (OOXML) / .XLSX

23.6 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: c3d10dbbcf4c2e491197e9b9bd8e1f74 SHA-1: 25f87517662528f2abbb95e78cf7ff43353b5c79 SHA-256: 781716e73ac749f94f6a239a2b58b25bcbe230235a58e88ae7510f1b4996b341
244 Risk Score

Malware Insights

Qbot · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The file contains Excel 4.0 macros that utilize WinAPI functions such as URLDownloadToFileA and ShellExecuteA. These macros are designed to download a second-stage payload from the URL https://backend.zafaranahouse.com/ds/26.gif and execute it. The ClamAV detection name 'Xls.Dropper.QbotDocu12020-9818439-0' strongly suggests the Qbot family.

Heuristics 6

  • Excel 4.0 macro sheet (1 sheet(s)) critical OOXML_XLM_MACROSHEET
    Spreadsheet contains an Excel 4.0 (XLM) macro sheet — XLM was a major Office malware vector during 2020-2022 and evaded many VBA-focused controls before Microsoft tightened XLM defaults. Even legitimate XLM use is rare in modern workbooks. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.
  • Binary XLM macro sheet with WinAPI/download strings critical OOXML_XLM_BINARY_WINAPI_STRINGS
    Excel 4.0 macro sheet is stored as BIFF12/XLSB binary data and contains Win32 download or process-execution API strings such as URLDownloadToFileA, ShellExecuteA, or CreateDirectoryA. These strings are high-signal in XLM macro sheets and catch payload-download macros that XML-formula scanners cannot parse.
  • XLM payload reassembled from CHAR()/split formulas critical OOXML_XLM_REASSEMBLED_PAYLOAD
    An Excel 4.0 macro sheet builds its payload inside the formula token stream by concatenating per-character CHAR() calls and string fragments, so no WinAPI name, shell command, or URL is ever contiguous in the .bin for a literal-bytes scan to find. Reassembling the formulas recovered download/execute API names, LOLBin commands (regsvr32/rundll32/mshta/wmic/powershell), or a payload URL — the de-obfuscated download-and-run kill chain.
  • ClamAV: Xls.Dropper.QbotDocu12020-9818439-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.QbotDocu12020-9818439-0
  • XLM payload URL string (1 URL) info OOXML_XLM_PAYLOAD_URL
    An Excel 4.0 (XLM) macro-sheet workbook with download/execute evidence carries a literal http(s) URL stored as a (often UTF-16) string in the shared-string table or a cell. This is the next-stage payload host referenced by the macro download chain (URLDownloadToFile/ShellExecute); surfaced as an IOC.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://backend.zafaranahouse.com/ds/26.gif

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin
581964282792c79e613320e827a7b43dd0b0bd59b511ea08bac1e7be04d2efb4		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 27387 bytes

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