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

Static analysis result for SHA-256 9787e15fcaf690b6…

MALICIOUS

Office (OOXML) / .XLSM

106.0 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: d4f59a456600cc66f4a826a02a9dfd3d SHA-1: a0cefeaea4599c067f7e753eb340234f497e1bcd SHA-256: 9787e15fcaf690b6d7ace0c2d93d07eecee9fec9bf58a6655947e1bd7715d48d
180 Risk Score

Malware Insights

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

The sample is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros. The macros utilize dangerous functions like CALL and EXEC, which are commonly used to download and execute arbitrary code. The embedded document body contains multiple URLs that are likely used as download sources for the payload. The presence of these functions and URLs strongly indicates a downloader or droppper functionality.

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: CALL, EXEC, FORMULA.FILL, HALT 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
63f9e5eb17c995d0e7d2ee834d0d2e49b6ccfcc236abef3c2751a08932270a4c		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 250355 bytes

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