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

Static analysis result for SHA-256 2f2a993289a24379…

MALICIOUS

Office (OOXML) / .XLSM

20.1 KB Created: 2021-03-24 09:58:11 UTC Authoring application: Microsoft Excel 16.0300
MD5: d1f541277dc46fb22cd09e2bdbd19f66 SHA-1: 6ceb58266a2167dfca1eb553b8846d347b883b8d SHA-256: 2f2a993289a24379089ca6e910f83b1b8efb79cb5088c4e77728ca3f90889558
120 Risk Score

Malware Insights

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

The file is an Excel macro-enabled sheet (XLSM) containing Excel 4.0 macros, specifically an Auto_Open macro. The document body contains social engineering text prompting the user to enable editing and content, which is a common lure for macro-based attacks. The presence of Excel 4.0 macros suggests an older, but still effective, delivery mechanism. The specific IOCs are related to XML namespaces within the document structure.

Heuristics 3

  • 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.
  • 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
    • http://schemas.microsoft.com/office/spreadsheetml/2014/revision
    • http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision3
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
855df0bbc933dce0cd825deb4c52e93551695753d10d4fb7b87e7bc9bbfda604		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 16849 bytes

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