Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 3683dfe7d6ca0aca…

MALICIOUS

Office (OLE) / .XLSX

142.6 KB Created: 2022-01-19 09:31:16 Authoring application: Microsoft Excel
MD5: 67143466f7730f0e0581299eceb2dd97 SHA-1: 07bc8ff7e6e1e3f00e7e015ec7ed0d0a885ff63f SHA-256: 3683dfe7d6ca0aca155aef7febcaf8434fe6545ad7937b3adaa2fdb2ee22fd80
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file is an Excel spreadsheet containing Excel 4.0 macros, specifically an Auto_Open defined name, which is a common technique for Emotet to execute malicious code. The ClamAV detection 'Doc.Downloader.EmotetExcel01220-9936774-0' further supports this attribution. The macro sheet appears to be designed 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.EmotetExcel01220-9936774-0 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

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