Emotet Office (OLE) / .XLSX malware analysis — malicious · 2307899d29ea25d1

MALICIOUS

Office (OLE) / .XLSX

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

MD5: e4ab43a5a359a7ca9d6b692af52313eb SHA-1: 3c2a888384a2aec55540aa86e7702afd81354283 SHA-256: 2307899d29ea25d1c7dfcda009141119f8247bf367616d522944a4f1c81f3138

140 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK

T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, a common technique for initial execution. ClamAV detection further confirms its malicious nature, specifically identifying it as an Emotet downloader. The document body, while appearing benign as a blood pressure tracker, serves as a lure. The primary attack vector is the execution of the embedded XLM macro upon opening the spreadsheet.

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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