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

Static analysis result for SHA-256 d892dc11ae95840a…

MALICIOUS

Office (OOXML) / .XLSX

91.8 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000
MD5: e2a74f2eb638c720c6fea729da0e3b84 SHA-1: 066be6dca9c980d0ea2ef39d49e4915cda8944c9 SHA-256: d892dc11ae95840a30b2c5a52b0cc7f0742b62810bba061deb8a7c8d65eb2662
60 Risk Score

Malware Insights

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

The critical heuristic firing indicates the presence of an Excel 4.0 macro sheet. The extracted script content reveals a WMIC command intended to execute a file named 'excel.rtf' located in the 'C:\ProgramData\' directory. This suggests the macro's purpose is to download and execute a second-stage payload from that location.

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
45ca36df8fb86bfe3eb6ccbed7abb6b047d717445e79dd924082c73bf7183d8c		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 165591 bytes

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