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

Static analysis result for SHA-256 d57ddda0daecea41…

MALICIOUS

Office (OOXML) / .XLSM

82.1 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 9f2e3824706f2408bbcb999bf5f85e5d SHA-1: 53a0eef3704a6b021b9bc59d6f69b25aee33241c SHA-256: d57ddda0daecea41b1563cb5c5d1878ce8f8badf22905d13bc0046a3ca8c7ac9
180 Risk Score

Malware Insights

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

This XLSM file contains Excel 4.0 macros, including an Auto_Open defined name, which is a common technique for initial execution. The macros utilize dangerous functions like CALL and REGISTER, indicating an intent to download and execute a second-stage payload from the embedded URL. The document body contains a suspicious URL that appears to be the target for this payload download.

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: FORMULA, CALL, HALT, EXEC 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
af384a0d22b21482d87725cea895ca85ecc490d0c3c4996a9b50d8f93e87ced4		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 19707 bytes
xlm_sheet_01.xml
d30d0bdbdc3063e69afc7d3c6401429aac87693165a049927be503c06d2c964c		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 1419 bytes
xlm_sheet_02.xml
644ddaecdc2c5458cffc5ad58ed19949086a06cf10b478a5857d1c4cd8813551		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 6156 bytes

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