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

Static analysis result for SHA-256 805f1ad7d66ea4c3…

MALICIOUS

Office (OOXML) / .XLSX

60.3 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000
MD5: 472d9bafdb09946b79d4a05042bbc961 SHA-1: 664877461034c5aeedcbbcaec7d61121d7dfc305 SHA-256: 805f1ad7d66ea4c39db27c4f5fb3c82bc72e2ff48f8e536b180a6161947682b9
60 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro sheet, which is a known method for delivering malicious payloads. The extracted script contains a WMIC command that executes 'mshta' to download and run a file named 'excel.rtf' from the 'C:\ProgramData\' directory. This indicates the macro's purpose is to download and execute 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
948e569b72e57a7f2d4df1a3ae7bf6a56921fafcaaf4ff0861686684cdbc4347		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 61356 bytes

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