Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 09bfef31d95e9892…

MALICIOUS

Office (OLE)

29.0 KB Created: 2010-09-09 01:12:55 Authoring application: Microsoft Excel
MD5: c631e75db226d850f37b0885ba6ab93d SHA-1: 557e849d23ae789ef2a4d4ec325a034b240631f7 SHA-256: 09bfef31d95e9892431a0640e7fc20908ef104d258da44d905d88c4f3ef12e4f
200 Risk Score

Malware Insights

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

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open macro, which is a known technique for legacy malware. The macros are designed to infect other workbooks and save them as 'Book1.xls' in the Excel startup directory, indicating a self-propagation or payload delivery mechanism. The presence of dangerous formula APIs like RUN further increases the risk.

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
ecbf0777e1248447c9c9b40f171d5b7ce3890e43ffdec4bcedec6e0616b9602b		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 9477 bytes

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