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

Static analysis result for SHA-256 49262f46a15258d7…

MALICIOUS

Office (OOXML) / .XLSM

23.0 KB Created: 2021-03-15 12:31:01 UTC Authoring application: Microsoft Excel 16.0300
MD5: 796e105620245de98c08a943e07c59fe SHA-1: 59e7f0120318b1b225d12e0fab971c8a85c5fa12 SHA-256: 49262f46a15258d7f43cc856db09e27b215cf1b3862ed9f391c56b7e434c2113
120 Risk Score

Malware Insights

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

The file is an XLSM document containing Excel 4.0 macros, indicated by the 'OOXML_XLM_MACROSHEET' and 'OOXML_XLM_AUTOOPEN_DEFINEDNAME' heuristics. The presence of an Auto_Open macro suggests an attempt to automatically execute code upon opening the document. While no specific URLs or scripts were extracted, the macro sheet structure itself is indicative of a downloader or initial execution vector. The confidence is moderate due to the lack of explicit payload URLs or script content.

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
85951543a940fcc1e17936a85866740a968a64fd264a024f9b7da02e1da4fd67		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 21865 bytes

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