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

Static analysis result for SHA-256 4d4b6fbf8392b5b2…

MALICIOUS

Office (OOXML) / .XLSX

83.9 KB Created: 2021-03-14 21:05:29 UTC Authoring application: Microsoft Excel 16.0300
MD5: 27eed9b95ce12d61e67046c1cae86d8a SHA-1: 0bb4203aa0851412702619e7880fc867027c1596 SHA-256: 4d4b6fbf8392b5b2b0145fb775c8e2774370494b84c7d30da68fa12639c08039
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is an Excel file containing Excel 4.0 macros. The heuristics indicate the presence of a macro sheet, which is often used to execute arbitrary commands or download additional payloads. The script content is heavily obfuscated and truncated, preventing a detailed analysis of its specific actions or any embedded URLs or commands.

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
b94045450eaa57909fbe3649146270747ef2e0f06c2119eb1c1458ac2ce61ca1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 88880 bytes

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