Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 bcebf33c0812a0eb…

MALICIOUS

Office (OLE) / .XLS

70.6 KB Created: 2022-01-20 19:00:43 Authoring application: Microsoft Excel
MD5: 1b2471823df460a058782aaf1177bb77 SHA-1: d9a66d02064556aa4dfe44c09a6d979dbc63baf4 SHA-256: bcebf33c0812a0eb18e5261449f212582882eb706df65f5d2f2dd9d3b2c05da1
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_AUTOOPEN_DEFINEDNAME indicate the presence of an Excel 4.0 macro sheet with an Auto_Open entry, which is a common delivery mechanism for Emotet. The ClamAV detection further supports this attribution. The macro is designed to execute automatically when the spreadsheet is opened, 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