Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 8f85561d2b7a899d…

MALICIOUS

Office (OLE) / .XLS

71.3 KB Created: 2022-01-20 19:00:43 Authoring application: Microsoft Excel
MD5: b9247d4f7c6fd5600b9c3f0a8380acdb SHA-1: 05f88138ef99abce524061966208067ddfcbc20d SHA-256: 8f85561d2b7a899d3c3f3b80aede779451737774e74cf567acd7943246c43e2f
140 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1566.001 Spearphishing Attachment

The critical heuristic OLE_XLM_AUTOOPEN_DEFINEDNAME indicates the presence of an Excel 4.0 Auto_Open macro, which is designed to execute automatically when the workbook is opened. ClamAV detection further confirms this as a known Emotet downloader variant. The macro sheet itself contains obfuscated code, but the presence of the Auto_Open entry is sufficient to classify this as a malicious document designed for initial payload delivery.

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.EmotetExcel01220-9937164-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetExcel01220-9937164-0
  • 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
7f1f89a8b36a750dced08313a4e4f056192a6eac7194357c673dbbd2670a1a18
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 4219 bytes