Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 4c2ddd629e265246…

MALICIOUS

Office (OLE) / .XLSX

71.1 KB Created: 2022-01-20 19:00:43 Authoring application: Microsoft Excel
MD5: 3dfb79a7933a9fbc037ba7682aea5815 SHA-1: d6cda0699a9c06b898f9bf3c2a462fe56e71c299 SHA-256: 4c2ddd629e265246f75b3e606e6bc899afb3c82020fc9a8f440e7793d6fed047
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The critical heuristic firings indicate the presence of Excel 4.0 macros, specifically an Auto_Open entry, which is a common technique for Emotet. ClamAV also detected the file as 'Doc.Downloader.EmotetExcel01220-9937164-0'. The macro sheet itself contains numerous LABELSST entries, suggesting it's designed to load and execute code. The presence of an Auto_Open macro strongly suggests the file is intended to deliver a malicious payload upon opening.

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

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