Emotet — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 c7665be16e6633d9…

MALICIOUS

Office (OOXML) / .XLSX

264.4 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-02-23
MD5: 588abfb77400b325002835769abff167 SHA-1: 00fb3f5ea0cd0f776e6f182b3e322b0456f23378 SHA-256: c7665be16e6633d97b36311d0d67c697c4d26ed628441039c9bf37d6bab74b4a
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 XLSX file. Heuristics indicate the presence of multiple macro sheets, and ClamAV detection explicitly names it as 'Xls.Downloader.Emotet-OOXML_XL'. The embedded macro sheets are heavily obfuscated, but the overall structure and ClamAV signature strongly suggest a downloader role, likely for the Emotet banking trojan. No specific URLs or executable payloads were directly extracted from the macro content itself.

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
9b2e50f12432ed6fd9de675753f0d9826331df24bd78153db79fd9eebafcc61d		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.bin 2451 bytes
xlm_sheet_01.bin
44d7986195da6c6db7ea97a0c0b6940f7c97cdda594fad3dfdc183b8f2cd5f14		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 484 bytes
xlm_sheet_02.bin
e1a8185f6a63ebad9ede83360d579b89743f240ad31c58cb55a11c9f4b137759		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.bin 484 bytes

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