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

Static analysis result for SHA-256 81422242c5bc4bf3…

MALICIOUS

Office (OOXML) / .XLSM

106.0 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 7eb1e4617768702afe8b08eb2168bd9e SHA-1: 0a6179b682d9ca573c523f71e90bce502a256bdf SHA-256: 81422242c5bc4bf3929e80e3aedb9324460d2deb9572afb2161a84acfc5c5d05
182 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an XLSM document containing Excel 4.0 macros, which are known to be used for malicious purposes. The macros utilize dangerous functions like CALL and EXEC to download and execute a payload from a list of provided URLs. The specific URLs identified are: http://gif.kristen.sbddev.com/ds/2803., http://kristen.sbddev.com/ds/2803., http://tienda.ventadigital.com.ar/ds/2803., http://thirdstringcalifornia.com/ds/2803., http://holmesservices.mobiledevsite.co/ds/2803., and http://nellaimasthanbiryani.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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