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

Static analysis result for SHA-256 851058ae164a79fe…

MALICIOUS

Office (OOXML) / .XLSM

106.0 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: cfb58165280201c5e31aa22a82f54b7b SHA-1: c162d1fce10f951e4751fbf6f962314b0fe1ab8c SHA-256: 851058ae164a79fed64868b78e7f1243eb158c61ad83cc368fd58eb0bc7e6690
182 Risk Score

Malware Insights

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

The file is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros. These macros utilize dangerous functions like CALL and EXEC, indicating an attempt to execute arbitrary code. The macros are designed to download a second-stage payload from one of the embedded URLs, such as http://gif.kristen.sbddev.com/ds/2803.

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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