Office (OOXML) / .XLSX malware analysis — malicious · 780d8ba81a8ddb54

MALICIOUS

Office (OOXML) / .XLSX

321.9 KB Created: 2021-08-16 09:36:27 UTC Authoring application: Microsoft Excel 12.0000

MD5: d88e7a53eea816822a4a46a639748911 SHA-1: 201c2ada0bcfc7f16cddc84668286f7844df80c2 SHA-256: 780d8ba81a8ddb54173a78f591241252c58583202ccd9dfeee860fd22915ebb5

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The critical heuristic firing indicates the presence of Excel 4.0 macros within the XLSX file. These macros are known to be used for executing arbitrary commands, often to download and execute further malicious stages. The truncated script content prevents a more detailed analysis of the specific commands being executed.

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.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `3212839a6cabe5b792123d87475b38068e8b40cd39d46b49ec000939c73d40ed`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	212644 bytes

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