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

Static analysis result for SHA-256 1fdce04a60bdebe9…

MALICIOUS

Office (OOXML) / .XLSX

73.0 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000
MD5: 91ad01b04989330b19630e46da84005f SHA-1: 0a8c32c43eeedd6077339e5b80a84da6c9e947f5 SHA-256: 1fdce04a60bdebe9ee7223d4315b9ff82dadb864b211d4df22bbf14e29a1a7f9
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Service Execution

The critical heuristic firing indicates the presence of Excel 4.0 macros. The extracted script content reveals a 'wmic process call create' command. This command is used to execute 'C:\ProgramData\excel.rtf', suggesting the macro's purpose is to download and execute a second-stage payload. The file's metadata shows it was authored by Microsoft Excel.

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
20bfcb2688d1872d97a325904a60d1845c1865addb32ee0766940a0844ffe821		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 58527 bytes

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