Emotet Office (OLE) / .XLSX malware analysis — malicious · 4520398e8aeabb1a

MALICIOUS

Office (OLE) / .XLSX

70.9 KB Created: 2022-01-20 19:00:43 Authoring application: Microsoft Excel

MD5: 98243298267d53aee8f08f98f7e897af SHA-1: 4ec1e8ce74bdd64d46648d4fcf80f2ccf76a9e59 SHA-256: 4520398e8aeabb1aed9cd4899a2ac014545d9ad9383959288cf2470f9c1c4731

140 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1059.005 Visual Basic T1204.002 Malicious File

The critical heuristics indicate the presence of Excel 4.0 macros, specifically an Auto_Open entry, and ClamAV detection points to Emotet. The XLM macro sheet likely contains code to download and execute a secondary payload, a common Emotet delivery technique. The ClamAV signature further supports the Emotet family attribution.

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.EmotetExcel01220-9937164-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Doc.Downloader.EmotetExcel01220-9937164-0
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` `7f1f89a8b36a750dced08313a4e4f056192a6eac7194357c673dbbd2670a1a18`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	4219 bytes

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