Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 200e8c9ae00a3203…

MALICIOUS

Office (OLE) / .XLSX

141.5 KB Created: 2022-01-19 09:31:16 Authoring application: Microsoft Excel
MD5: 898f8d42ad1155cf3f7c06028c3f6cc1 SHA-1: 27a325fa829b6ce5086a245b63b82c82c914f1ef SHA-256: 200e8c9ae00a3203aec36692f6a0a308dcc54d4b197115c599c678ebfaee3c18
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file is identified as malicious by ClamAV with the signature Doc.Downloader.EmotetExcel01220-9936774-0, indicating it is a known Emotet downloader. Critical heuristics confirm the presence of Excel 4.0 macros with an Auto_Open entry, which is a common delivery mechanism for Emotet. The macro sheet is configured to execute code automatically when the workbook is opened, typical for downloading and executing further stages of the malware.

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