Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 4c24109a4627af0b…

MALICIOUS

Office (OLE) / .XLSX

145.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: e4b875606b867ca3356e22cd2dc3203f SHA-1: d7aff240d9626f44fcecf541b0548f4a624dc0fc SHA-256: 4c24109a4627af0bf5480d142ed639a34c09df00a4e8d442d667c35b0ac3e684
262 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro. This macro is designed to execute dangerous functions and reconstructs a list of URLs from cell arrays. These URLs are likely used to download and execute a second-stage payload. ClamAV detection further supports this assessment, identifying it as Doc.Downloader.EmotetRed02222-9938635-0.

Heuristics 6

  • 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.
  • URL reconstructed from XLM cell array (5 URLs) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime) or across individual numeric cells (one ASCII charcode per cell). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries plus LABELSST/RK/NUMBER cells.
  • ClamAV: Doc.Downloader.EmotetRed02222-9938635-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetRed02222-9938635-0
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://terrassa-cafe.com/9yjxnes/18p2S7bBrdpM6FrAc/
    • https://moseletronicos.com/wp-content/5/
    • https://sabaithaimassage.com.au/wp-admin/Hgbn3e/
    • https://wiremax.avaspadan.com/admin/ItopibIZF3dxpy0/
    • https://troopsites.com/wp-admin/CzMJm2vfbA4osSHH/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
71a011c6654bf0f86fe42dabbb7815a8e04c6ae15b5b70864945acbb6f82ced0		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6768 bytes

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