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

Static analysis result for SHA-256 83855f02aa72bd05…

MALICIOUS

Office (OOXML) / .XLSX

196.3 KB Created: 2021-02-27 09:36:14 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2026-05-21
MD5: 18d2d285be4ab4b1bf10763ca0a41625 SHA-1: 807179f2ef97886c299f04d4aded50a53888a6a3 SHA-256: 83855f02aa72bd051fe7cb5e0457a5402bc38a54882417d141af450641986fb9
60 Risk Score

Malware Insights

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

The file is an Excel spreadsheet containing Excel 4.0 macros, which are known to be used for malicious purposes. The macros are likely designed to download and execute a second-stage payload, a common technique for initial execution and further compromise. Due to the obfuscated nature of the macro content, specific IOCs could not be extracted.

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 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 8324 bytes
SHA-256: ca1f9014ff993aa2a9154dd9946b9157465b771a7c180d4e2ec78a50d9436ad5
Preview script
First 1,000 lines of the extracted script
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... (truncated)

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