Emotet — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 2fab1a66c573c4e9…

MALICIOUS

Office (OOXML) / .XLSX

135.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: dded6ffeac57575360cc5804e8969394 SHA-1: e2b4622e2227b595431ac8d53ffb5ff42b7fc6bf SHA-256: 2fab1a66c573c4e9c5da681e5914935c39c7cb685bff5fdeaa6b9e2661adf46c
180 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample is identified as malicious by ClamAV as 'Xls.Downloader.Emotet-OOXML_XL-af43432fbcb8603c-9980048-0'. Static analysis revealed the presence of Excel 4.0 macros within an XLSX file, a known technique for delivering Emotet. The macros are likely responsible for downloading and executing a second-stage 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
b209e4b6f256be59066e837c1b1c62ea2edf06d3fcf8cd507b47e2aac058fc27		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.bin 1858 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.