Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 a94875a62546e0ff…

MALICIOUS

Office (OLE) / .XLSX

142.1 KB Created: 2022-01-19 09:31:16 Authoring application: Microsoft Excel
MD5: 5bffdae22f776d781cab2ad5309a6154 SHA-1: 7943586d63be16066060c5482073b1313cbc78b0 SHA-256: a94875a62546e0ff04e0a0ff648b48bc6ad7071b539a8d41c8d1176ce4e1252b
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a strong indicator of malicious intent. ClamAV detection confirms this, identifying it as 'Doc.Downloader.EmotetExcel01220-9936774-0', a known Emotet downloader variant. The macro sheet is designed to execute automatically when the workbook is opened, likely to download and execute a secondary payload.

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