Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 29a765d282e097a0…

MALICIOUS

Office (OLE) / .XLSX

143.0 KB Created: 2022-01-19 09:31:16 Authoring application: Microsoft Excel
MD5: ab7fe725f889ed937d23d56ad819176b SHA-1: 1b5dffb07b9b224834a758d1c2510dcef5ee2ce4 SHA-256: 29a765d282e097a0ddcba25fb078bb0b81fbf9a3e5939f0be8bf41c72c770f83
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 entry, which is a known technique for executing malicious code. ClamAV detection confirms this as 'Doc.Downloader.EmotetExcel01220-9936774-0', strongly indicating an Emotet downloader. The document body, while appearing benign as a blood pressure tracker, serves as a lure for this macro-based execution. The primary function of the macro is 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