Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 fbcba24f92756db5…

MALICIOUS

Office (OLE) / .XLSX

60.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-14
MD5: 17bc162c86e4b2d5764df1a52137c0e8 SHA-1: 72735b36b6da41f66baccc34602ca1d949fed372 SHA-256: fbcba24f92756db5f1bce80dbc40b9f8c5629d871f72f5bc5336ad5e644c10ef
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for Emotet. The macros are designed to execute a dangerous formula API, likely to download and run a payload from one of the provided URLs. ClamAV also detected this file as Xls.Downloader.Emotet.

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-ea85817e7e81383e-9951566-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-ea85817e7e81383e-9951566-0
  • 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
81a890043a2bf9bada66e5f829f683706b013cf3d1f82e11ea536e934629d60f
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8316 bytes