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

Static analysis result for SHA-256 15ea954969e6357a…

MALICIOUS

Office (OOXML) / .XLSM

92.6 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: e76db0743b161045a90579f1d9368972 SHA-1: feb02dcacf5604c887bfac2caff9535f5199e010 SHA-256: 15ea954969e6357ab168b7b913b261585cb1a6a361fe17c9b4fae98bff5d5fc8
182 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an XLSM document containing Excel 4.0 macros, indicated by critical heuristic firings for XLM_MACROSHEET, XLM_AUTOOPEN_DEFINEDNAME, and XLM_DANGEROUS_FN. The macros utilize dangerous functions like CALL and EXEC, which are used to download and execute payloads. The embedded URLs are reconstructed from the document body and scripts, pointing to potential second-stage download locations.

Heuristics 4

  • Excel 4.0 macro sheet (1 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: EXEC, HALT, CALL, FORMULA.FILL 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
b2aa95d3b3a02526f200b3d969c9988b4d5832e6c13ac8dcb3a1d9eb395b3574		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 213450 bytes

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