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

Static analysis result for SHA-256 68fd3b003088b871…

MALICIOUS

Office (OOXML) / .XLSX

81.3 KB Created: 2021-02-26 07:53:41 UTC Authoring application: Microsoft Excel 16.0300
MD5: bfdb8d0545b04bb2be7ad6673d1a0362 SHA-1: 0637360cc54843bd89556e2ce25bd8ae981b7bb6 SHA-256: 68fd3b003088b871755da305be7a7126890c3787eefbc7272bcd4d0015606d65
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is identified as an Excel 4.0 macro sheet, a known technique for executing malicious code. The embedded XLM macro sheet likely contains instructions to download and execute a secondary payload, although the specific commands are truncated in the provided evidence. This points to a downloader or dropper functionality.

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
ef997699b9339c8fafb49bb927cd92d5a1e1c643ccbc67601cc1d21fce8363dc		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 4569 bytes

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