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

Static analysis result for SHA-256 534f7404e22e5043…

MALICIOUS

Office (OOXML) / .XLSX

59.7 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000
MD5: 4947ab39eaca5f886a5a7ebf2d6ed4f1 SHA-1: 8fb7a53063a3d500908cc661a3ffc5f7923c19f2 SHA-256: 534f7404e22e504303742731ed8b74a5f7b969e5d3077fff0cf79b357d424b02
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The critical heuristic 'OOXML_XLM_MACROSHEET' indicates the presence of Excel 4.0 macros. The embedded script content, though truncated, shows a clear attempt to construct a path to 'C:\ProgramData\excel.rtf', suggesting the macro's purpose is to execute a file from this location. This is a common technique for downloading and running a second-stage payload.

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
ddaa92eeb0959fe49bc1728770a1dd4fb32caf8017ca0b9e70939326db638f6b		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 165942 bytes

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