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

Static analysis result for SHA-256 00878a7fd37466d3…

MALICIOUS

Office (OOXML) / .XLSX

68.0 KB
MD5: 40889adb35b8b6003cd9183029bbeda4 SHA-1: f527d144f6057a69566bf5065e75bcb00503fa45 SHA-256: 00878a7fd37466d3a7e5767a11df6772d18daff23a34ff009b1d71a9d2489545
190 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the use of dangerous XLM formula APIs like FORMULA, which can call Win32 functions. This suggests the macro is designed to execute arbitrary code, likely to download and run a secondary payload. No specific IOCs were extracted, but the technique is indicative of a downloader or initial access stage.

Heuristics 5

  • Excel 4.0 macro sheet (3 sheet(s)) critical OOXML_XLM_MACROSHEET
    Malformed OOXML local headers contain an Excel 4.0 (XLM) macro sheet. XLM was a major Office malware vector during 2020-2022 and is rarely used in modern legitimate workbooks.
  • Dangerous XLM formula APIs: FORMULA critical OOXML_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet uses formula APIs that call directly into Win32 (=CALL/=EXEC/=REGISTER/=FORMULA).
  • ClamAV: Win.Malware.Agent-9983616-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Malware.Agent-9983616-0
  • Malformed OOXML package with recoverable local headers low OOXML_MALFORMED_ZIP_LOCAL_HEADERS
    The OOXML ZIP central directory is invalid or missing, but local file headers expose a recoverable Office package. This can create parser divergence between tolerant Office/ZIP readers and scanners that rely only on the central directory.
  • 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_08.xml
5a62a357cb895c98dc30b4c4c5c056eac8ac1b92bc088a5bcf20517cbcd838f8		 xlm-macrosheet Malformed OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3434 bytes
xlm_sheet_09.xml
c70a51acb5791492ef3f1e96d2217abba4360bc0964fdbbf0b281da430450073		 xlm-macrosheet Malformed OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 908 bytes
xlm_sheet_10.xml
84b5606b26315521210c94dce2556ab11c1d4148efb57521cf114d2065ef725b		 xlm-macrosheet Malformed OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 905 bytes

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