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

Static analysis result for SHA-256 a56a0820ddff214b…

MALICIOUS

Office (OOXML) / .XLSX

69.5 KB Created: 2021-03-14 21:05:29 UTC Authoring application: Microsoft Excel 16.0300
MD5: 35e480649ab25c189af264d2e4a66e99 SHA-1: b17a76920d245d9a322a239a669bd7b262a16838 SHA-256: a56a0820ddff214bb55156db3e642ac2dd91163eb79fd6c68cbcad4a71edd3cf
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is an Excel file containing Excel 4.0 macros, indicated by the OOXML_XLM_MACROSHEET heuristic. While the macro content is heavily truncated and obfuscated, this technique is commonly used to download and execute second-stage payloads. The exact nature of the payload or its delivery mechanism cannot be determined from the provided evidence.

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
a392b624eb235a4d9c9f8edebe747520df76df62bd00b43234ac708b2734a714		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 88880 bytes

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