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

Static analysis result for SHA-256 52f717a65e45ed4f…

MALICIOUS

Office (OOXML) / .XLSX

86.1 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000
MD5: bea1216f2c9a28e751d02187eb520b55 SHA-1: 85daf1d864e49f5c772b87287f78ea55b08ef005 SHA-256: 52f717a65e45ed4fdaf8f157d25c4bd5f8d943f7ec0bf74bffb533e0881ec591
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file is an Excel spreadsheet containing an embedded Excel 4.0 macro sheet. The macro appears to be attempting to execute a command that references a file path 'C:\ProgramData\excel.rtf', suggesting it's designed to download and run a secondary payload. The macro is heavily obfuscated and truncated, limiting deeper analysis.

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
ea990e82fad16567371c2266d7cdc6a6a8f2e1c029a5827824ee89b6b454ee53		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 299074 bytes

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