Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 ee212ba040e6857e…

MALICIOUS

Office (OLE) / .XLSX

142.9 KB Created: 2022-01-19 09:31:16 Authoring application: Microsoft Excel
MD5: 740c3a1122de26f6c318e1a14c0b44cf SHA-1: 35f1fc2bd5b76ba2510f23efa6002e94415fb035 SHA-256: ee212ba040e6857e56a3e2e8be38c52d0501f8a315b6c9599c63aa1490cd5ac3
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file contains critical heuristic firings indicating the presence of Excel 4.0 macros with an Auto_Open entry, a known technique for Emotet. ClamAV also detected it as 'Doc.Downloader.EmotetExcel01220-9936774-0'. The macro sheet appears to be designed to execute code automatically when the workbook is opened, consistent with a downloader's behavior.

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