Emotet — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 9069c3730cb0bc2f…

MALICIOUS

Office (OOXML) / .XLSX

199.7 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 9081c569be99d616d2853693e00a6b0b SHA-1: a427c97e92b3f2867bcbd2e48d97152555ae5abc SHA-256: 9069c3730cb0bc2f5e37c03accc8f584892d29537e35067ee0e08b9611967d49
180 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File

The sample is identified as an Excel 4.0 macro sheet, a known delivery mechanism for Emotet. The ClamAV detection explicitly names Emotet and indicates a downloader function. The presence of Excel 4.0 macros strongly suggests the intent to execute arbitrary code, likely to download and run a secondary payload.

Heuristics 3

  • 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.
  • XLSB international XLM macro sheet hidden in .xlsx critical OOXML_XLSB_INTL_MACROSHEET_IN_XLSX
    OOXML package is named .xlsx but contains XLSB workbook parts and an international Excel 4.0 macro sheet. This hides XLM macro execution from scanners that trust the extension or only inspect XML worksheet parts. The technique is macro execution, not a document-parser CVE.
  • ClamAV: Xls.Downloader.Emotet-OOXML_XL-af43432fbcb8603c-9980048-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-OOXML_XL-af43432fbcb8603c-9980048-0

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin
da24ffe05f4ee580b21a02638eba973d099a83f0af41af14c87170b4eb6834b9		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.bin 1799 bytes

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