Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 901080be2ebddd84…

MALICIOUS

Office (OLE) / .XLSX

71.3 KB Created: 2022-01-20 19:00:43 Authoring application: Microsoft Excel
MD5: efb3f62043e41427d07fedf61f4ae2f6 SHA-1: 457bd6a05151384cd164cd92ddd6abc72e93cabc SHA-256: 901080be2ebddd84578b1c86870709fc36d04777bb2a6baa69234b7aab046a1a
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 initial execution. ClamAV detection further confirms its malicious nature, identifying it as Emotet. The presence of an Auto_Open macro suggests the file is designed to run malicious code immediately upon being opened by a user, fitting the pattern of a downloader or initial access vector for the Emotet family.

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