Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 ad511015e8c542a0…

MALICIOUS

Office (OLE) / .XLSX

141.1 KB Created: 2022-01-19 09:31:16 Authoring application: Microsoft Excel
MD5: 209cf65ce75019e061ddcb09f4ac6e2f SHA-1: cf3efd3f2a615656888209ae76ad914c8d8eda56 SHA-256: ad511015e8c542a03954c1be8721ddcce85dbe997f7b2048bc6e1b35823c5ffc
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a common technique for Emotet to execute its initial payload. ClamAV also detected it as 'Doc.Downloader.EmotetExcel01220-9936774-0'. The document body, while appearing benign as a blood pressure tracker, is likely a lure to entice users to open the malicious macro-enabled spreadsheet. The primary function of the macro is to download and execute a secondary 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