Emotet Office (OLE) / .XLSX malware analysis — malicious · d191978b33baf418

MALICIOUS

Office (OLE) / .XLSX

142.9 KB Created: 2022-01-19 09:31:16 Authoring application: Microsoft Excel

MD5: f0ecdfd24c7d544fc95e2510ea83a8ca SHA-1: b1817486a6c69598ccbec33da7c2167866979621 SHA-256: d191978b33baf418a4d91965e7b1b718e1cba6cdcefb9e47387e1f97069517ed

140 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK

T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_AUTOOPEN_DEFINEDNAME indicate the presence of an Excel 4.0 macro with an Auto_Open entry, which is a common delivery mechanism for Emotet. ClamAV detection further supports this attribution. The macro sheet contains references to sheet names like 'Blood Pressure Data', suggesting a lure document. The primary function of this macro is to execute arbitrary code, typically 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.

Filename	Kind	Source	Size
`xlm_macros.txt` `592af8991900f2f7058dc7ea90a33320ae293c7e541db4222a7b7f9c04f59d96`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	8469 bytes

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