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

Static analysis result for SHA-256 c73ed14ba72eaabb…

MALICIOUS

Office (OOXML) / .XLSM

78.6 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 0683355cf49dbfa8fb2865a1c5e72633 SHA-1: 454e26997a9ecdd570706f637241c1a5619b7d4f SHA-256: c73ed14ba72eaabbb2c2f72626ba0cddfb59b88d47f3f354bf0c1b37b8759fe6
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1105 Ingress Tool Transfer

The sample is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros. These macros utilize dangerous functions like HALT, which are known primitives for downloading and executing payloads. The document body contains a URL that likely points to the payload. The presence of Auto_Open and the use of direct Win32 API calls strongly suggest a downloader functionality.

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: 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
emf_00.emf
ab58818ae1864807b22f8a58a75f7fa8703ecb19a2352bdb47469f366b868e59		 ooxml-emf OOXML EMF part: xl/media/image7.emf 1108 bytes
xlm_sheet_00.xml
b0e85f6bacf2890dc468a4764fcbce58b394ed7e564bc0b3da61c56304c19129		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1191 bytes
xlm_sheet_01.xml
306ff6a7899a074e0a012be462c396a92105fbe2e1be1a05082e864765645191		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1977 bytes
xlm_sheet_02.xml
18d2ba72cca43907b6d94db49251f3b93c6db105d752d00819dcdc7382d0f43f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 993 bytes

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