Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 af8a68f94619d116…

MALICIOUS

Office (OLE) / .XLS

109.0 KB Created: 2022-01-22 10:28:51 Authoring application: Microsoft Excel
MD5: 9ddc480f2fc034e816938e15cf84494a SHA-1: bfe1ee33d17eb11be1526e5cfd672101bfa66264 SHA-256: af8a68f94619d1169268281a16aba6cf09f5c52aa0f5abab7131d7f22c5d1f77
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The critical heuristic OLE_XLM_AUTOOPEN_DEFINEDNAME indicates the presence of an Excel 4.0 Auto_Open macro, which is a common delivery mechanism for Emotet. ClamAV also explicitly detected the file as 'Xls.Downloader.Emotet'. The macro sheet is likely designed to download and execute a second-stage payload.

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: 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
4282a66cb39a54151a7150b41c26dfb71d035cb8ac904f3e031d21c44da4ada6
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3523 bytes