Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 934cbb40fb991a65…

MALICIOUS

Office (OLE) / .XLSX

142.6 KB Created: 2022-01-19 09:31:16 Authoring application: Microsoft Excel
MD5: eedaddafc0b2a475895656b7fc4b7824 SHA-1: 42b918bb71660bfa1ae4f72a3efe179abe58d6e3 SHA-256: 934cbb40fb991a65966c7890bb328974e9779cfac8370eda488b5c72e7b255fe
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 an Excel 4.0 macro sheet with an Auto_Open entry, a known technique for Emotet. ClamAV also detected the file as 'Doc.Downloader.EmotetExcel01220-9936774-0'. The macro sheet is likely designed to execute automatically and download a secondary payload, consistent with Emotet's typical 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