Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 da59d7ca5d09854f…

MALICIOUS

Office (OOXML) / .XLSM

82.2 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 3bd29a82d7f72e8a5d2541c110269bb8 SHA-1: 8519a58550ce732ee506af75ccb75f7f12f5823d SHA-256: da59d7ca5d09854ff20bef46758a4c80eafc0dd5fec36968075fbcbef2cc0ed5
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File T1059.001 PowerShell

The sample is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros. Critical heuristics indicate the use of dangerous XLM functions like CALL and EXEC, which are commonly used to download and execute arbitrary code. The embedded URL in the document body is likely the source of the payload. The macros are designed to download and execute a second-stage payload from the specified URL.

Heuristics 4

  • Excel 4.0 macro sheet (3 sheet(s)) critical OOXML_XLM_MACROSHEET
    Spreadsheet contains an Excel 4.0 (XLM) macro sheet — XLM was a major Office malware vector during 2020-2022 and evaded many VBA-focused controls before Microsoft tightened XLM defaults. Even legitimate XLM use is rare in modern workbooks.
  • Excel 4.0 Auto_Open defined name critical OOXML_XLM_AUTOOPEN_DEFINEDNAME
    Workbook defines _xlnm.Auto_Open or _xlnm.Auto_Close while containing an XLM macro sheet. This is the OOXML/XLSB auto-execution shape for Excel 4.0 macros.
  • Dangerous XLM formula APIs: FORMULA, CALL, HALT, EXEC critical OOXML_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet uses formula APIs that call directly into Win32 (=CALL/=EXEC/=REGISTER/=FORMULA). These are the primitives used to download payloads, write files, and start processes from an XLM macro without invoking VBA.
  • 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 http://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.microsoft.com/office/excel/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
92e029e4df7d07011197ed2fdc9fdb82ce9a048ae0564b1d71a1dc32f8dc1512		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 6866 bytes
xlm_sheet_01.xml
5e0b317bc9eef478a9b391aa848d4ca25c6a2921bbc6af4ad6fc140f76188572		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 963 bytes
xlm_sheet_02.xml
ba879ec0f64b30e11e9087bbe56136dfd84f79126134f6d66e265bd1a4b7287c		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 2154 bytes

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