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

Static analysis result for SHA-256 e889578e4e83a086…

MALICIOUS

Office (OLE) / .XLS

71.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 7dda9c6550f3523f8511aa772bd0e77e SHA-1: 81ed0d0677e1772c085ee722e319f55bb6762fdb SHA-256: e889578e4e83a086f09986c77d3cf69e2ae055a0dbbac09f1988a35aad8a8b21
200 Risk Score

Malware Insights

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

The file is an Excel 4.0 (XLM) macro-enabled spreadsheet. Critical heuristics indicate the presence of an Auto_Open macro, which is a known technique for executing malicious code upon opening the document. The macro sheet contains references to 'XL4Poppy', 'Classic.Poppy by VicodinES', and 'Excel Formula Macro Virus (XF.Classic)', suggesting it's a variant of a known legacy macro virus. The script also attempts to infect other workbooks and save them as 'Book1.xls' in the XLSTART directory, indicating a delivery mechanism for further infection.

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
a31d5889f2f957a8f56b6058fcb0d6fe153d777fdb44ea2c6d459af1e1ae7df0		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 53576 bytes

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