Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 dc30b62a76919332…

MALICIOUS

Office (OLE) / .XLSX

141.3 KB Created: 2022-01-19 09:31:16 Authoring application: Microsoft Excel
MD5: ab70f53b7134d9642ddc9c194ba38b6c SHA-1: 275d1d45b82efbd2f2d287acf3d4e55d1c6bae7c SHA-256: dc30b62a769193329abed9180d616186d643f208dda5a717411bbcac8d387c0a
140 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.005 Visual Basic

The file is identified as malicious by ClamAV with the signature 'Doc.Downloader.EmotetExcel01220-9936774-0', indicating it's a known Emotet downloader. Critical heuristics confirm the presence of Excel 4.0 macros with an 'Auto_Open' entry, which is a common execution vector for this family. The macro sheet itself contains references to sheet names like 'Blood Pressure Data', suggesting a lure document. The primary function of the Excel 4.0 macro is to execute code automatically when the workbook is opened.

Heuristics 3

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • ClamAV: Doc.Downloader.EmotetExcel01220-9936774-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetExcel01220-9936774-0
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
592af8991900f2f7058dc7ea90a33320ae293c7e541db4222a7b7f9c04f59d96
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8469 bytes