Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 51dc452edd7c975a…

MALICIOUS

Office (OLE) / .XLSX

70.7 KB Created: 2022-01-20 19:00:43 Authoring application: Microsoft Excel
MD5: 2a79c56d99d3b1f6e43efad1f455f56b SHA-1: 30e782c6d28f73f0b22752b0e07fe07a7e113dfe SHA-256: 51dc452edd7c975ac8f632ad888d6cada4233c19aa061416076abbdb2ac596b4
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The critical heuristics indicate the presence of Excel 4.0 macros, specifically an Auto_Open defined name, which is a common execution vector for Emotet. ClamAV detection further confirms this classification. The presence of an Auto_Open macro suggests the file is designed to automatically run malicious code upon opening, likely to download and execute a second-stage 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.EmotetExcel01220-9937164-0 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