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

Static analysis result for SHA-256 8393a4adfc52b821…

MALICIOUS

Office (OOXML) / .XLSM

120.1 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 23723cbba5a0c4a19cd6bbf91f884f7c SHA-1: 8ac83c33d6696122abfdaca85b16cbc2a44b06e3 SHA-256: 8393a4adfc52b82181fc5008601df84de01dd48cbb539d06a006eb93d271eb3d
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: User Execution: Malicious File T1059.001 Command and Scripting Interpreter: PowerShell

The sample is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros. The macros utilize dangerous functions like CALL and EXEC, indicating an attempt to download and execute a second-stage payload from one of the provided URLs. The presence of these functions and the embedded URLs strongly suggest a malicious downloader.

Heuristics 4

  • Excel 4.0 macro sheet (2 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 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
07f4642ae693bcda0109647800937a545625151cf00c4004cbf3c380d0c360e6		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 744 bytes
xlm_sheet_01.xml
d0f00d5ec29552a4ac33f37541f0ec4947e2b9ca3e0e12d642423d0b6b2e1c40		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 207680 bytes

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