Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 572387e1541823e6…

MALICIOUS

Office (OLE) / .XLS

95.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-07-13
MD5: a859bf4d9261cb6dbf0f67ee078eb107 SHA-1: c0fbb7fa04f0f1b15e32edb376fec46d22d4aa92 SHA-256: 572387e1541823e69d42b208d74253dddfe19d20f2f5d67ecb232b897e510e9e
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample is identified as malicious by ClamAV with the signature Xls.Downloader.Emotet-ea81817e7f807ab1-9952142-0. Critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a known technique for Emotet to execute its initial payload. The macro sheet contains dangerous formula APIs, including RUN, suggesting it is designed to download and execute a secondary stage.

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
85773188e79d904ef8ecf815a27f3a8200cc87e1822ab4901cc9bed29c53e636		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8156 bytes

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