Emotet — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 415d7022841d3e4e…

MALICIOUS

Office (OOXML) / .XLSX

258.5 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-02-15
MD5: 374f73c36c913cc0f091c0ca77193027 SHA-1: f0a130b075fa0bd05f49e1a539ae1c62c9763830 SHA-256: 415d7022841d3e4ee546295bb3bf061bb5dfef99dc55fa99a23ab8f69666facf
180 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic

The sample is identified as an Excel 4.0 macro-enabled document, a common delivery mechanism for Emotet. The ClamAV detection explicitly names Emotet and indicates a downloader function. The embedded XLM macrosheets, though truncated in the provided evidence, are consistent with the typical behavior of Emotet droppers which execute code to fetch and run further malicious stages.

Heuristics 3

  • Excel 4.0 macro sheet (3 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin
cd9549f3f60544f853c00b5eb3c8e486b8cb1bce93764246b9121e5f259d7ccc		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.bin 2474 bytes
xlm_sheet_01.bin
4a5404e13cad24023f87ffa3d548dcb34420bc3d95ce11a786e95d9855762755		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 484 bytes
xlm_sheet_02.bin
dd6a2b630c56356919ca960b5050e7da4cbf2eb4d6dd2eaf22033eff1a33c2fa		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.bin 484 bytes

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