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

Static analysis result for SHA-256 b0494eb21c852292…

MALICIOUS

Office (OOXML) / .XLSM

81.2 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 36dbab140282b3e3272a5223298c617a SHA-1: 755697fd4cc4bdb2af44ea902cd52e7029b2e0c4 SHA-256: b0494eb21c852292169aa0de2c0d5f897f23b4047778555e203b00ef46b3340b
180 Risk Score

Malware Insights

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

The file is an XLSM document containing Excel 4.0 macros. Heuristics indicate the use of dangerous XLM functions like CALL and EXEC, which are commonly used to download and execute payloads. The document body contains a URL that appears to be related to payload delivery. The macros likely download and execute a second-stage payload from the embedded 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
cbfd740c03b1bf3d9d71e7c947054d533d25b95cc1f6077c88f12f5af6114aa2		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 1687 bytes

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