Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 879d9ef859733dda…

MALICIOUS

Office (OLE) / .XLSX

96.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-07-12
MD5: febf4a953df995efe16c2d13d55b6612 SHA-1: d1b67d3cc02d586e01907f10c4cf9ad2acb9430e SHA-256: 879d9ef859733dda7eeebcab9b3514d96522a0c525d6bb5f80a1a48c4fb75eb4
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. ClamAV detection identifies this as Emotet, a downloader family. The macro sheet contains dangerous formula APIs, including RUN, indicating an attempt to execute arbitrary commands.

Heuristics 4

  • 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.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • ClamAV: Xls.Downloader.Emotet-ea81817e7f807ab1-9952142-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-ea81817e7f807ab1-9952142-0
  • 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
44b7c45128c9ebff1e2d4c700363a400191ad3820db3f6fdcc49f6028eab1dc9		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8173 bytes

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