Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 3daae0100fd20895…

MALICIOUS

Office (OLE) / .XLS

133.0 KB Created: 2010-08-09 15:05:18 Authoring application: Microsoft Excel
MD5: 1c65e8cad4510524102b297fdfeb542f SHA-1: 2fdf13438c7aa50ea436937984983d1e5d810519 SHA-256: 3daae0100fd208958f1eed9945663de34a27270cad082ae237f20b110a117463
200 Risk Score

Malware Insights

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

The file is an Excel 4.0 (XLM) macro-enabled workbook. Heuristics indicate the presence of an Auto_Open macro, which is a known technique for executing malicious code upon opening the document. The macro uses dangerous functions like RUN, suggesting it is designed to execute arbitrary commands. While the specific payload is not directly visible, the presence of Auto_Open and the use of RUN strongly indicate a downloader or initial execution stage for a more complex attack.

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.
  • Legacy Excel formula macro virus marker critical OLE_XLS_FORMULA_MACRO_VIRUS
    Workbook stream contains self-identifying legacy Excel formula macro virus markers. This indicates the document carries formula macro virus content even when no VBA project or modern XLM macro-sheet structure is present.
  • 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
04e3de2fe9183a9720709a184eac06c5825493d5c96f801075a1831e951d8b35		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 128705 bytes

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