Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 5f614f6af330dddd…

MALICIOUS

Office (OLE) / .XLSX

115.2 KB Created: 2022-01-24 14:50:55 Authoring application: Microsoft Excel
MD5: d1324007b3119b5411a1ea61e481e3f1 SHA-1: 2b310992121b528e0118b12e8e68ecbe9589cdbc SHA-256: 5f614f6af330dddd0d71a2cb70c771087a1ffaac2765bbad8e0326bd97b9c1c8
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file contains Excel 4.0 macros, specifically an Auto_Open entry, which is a known technique for executing malicious code. ClamAV detection identifies it as an Emotet downloader. The macro sheet contains dangerous formula APIs, indicating it's designed to run code, likely to download and execute a secondary payload.

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-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
f65423032a2492710482664c048191ebe835ee4ace2752f1b0fa6e40d416cdf9
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 4885 bytes