Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 239f5f4bf79218e5…

MALICIOUS

Office (OLE) / .XLS

53.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-23
MD5: 8a8bbc9bb6e234e07a33b8396cd7eb20 SHA-1: 55073bf36df269fb0631a8404a38f93b581c686e SHA-256: 239f5f4bf79218e55b315045cb684d67a705f54a6fdb5a99516193cdca112693
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that utilizes dangerous functions, specifically the RUN function. The macro sheet contains concatenated strings that, when reconstructed, form multiple URLs. These URLs are likely used to download and execute a second-stage payload, consistent with Emotet's typical delivery mechanism. The ClamAV signature also confirms the Emotet family.

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-b3b8ccc73b3840c7-9950421-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-b3b8ccc73b3840c7-9950421-0
  • 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
cdf609d5e26a49338c61a9a3392ed69e82eedf772bf35749fa05298fa3f8988d		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7783 bytes

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