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

Static analysis result for SHA-256 a0ee31f222f7b6b4…

MALICIOUS

Office (OOXML) / .XLSX

85.9 KB Created: 2021-03-15 18:19:11 UTC Authoring application: Microsoft Excel 16.0300
MD5: e0478696c5fd0f601eebb3783cc470dc SHA-1: f95d0ca9719a54e40ff9ec07ec75561ccf0626cc SHA-256: a0ee31f222f7b6b4967878a34cd525ff2ad33a817d0d8aeb0064562cdb568fd6
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is an Excel file containing a macro sheet, indicated by the OOXML_XLM_MACROSHEET heuristic. The extracted macro content is heavily obfuscated and truncated, making it difficult to determine the exact payload. However, the presence of Excel 4.0 macros strongly suggests an attempt to execute arbitrary commands upon opening the document.

Heuristics 1

  • 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. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin
8256b4eb17a8289dcef04247b68000b42585c7886fa4627de6cb038ece741c73		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 96758 bytes

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