Office (OOXML) / .XLSX malware analysis — malicious · 10a1c07d93bf4917

MALICIOUS

Office (OOXML) / .XLSX

81.3 KB Created: 2021-02-26 07:53:41 UTC Authoring application: Microsoft Excel 16.0300

MD5: be3399b5d8f68ebbae7aaa66a6581fb2 SHA-1: a62b6d1e9c84d7622ad0028ff4b9caa433ffa960 SHA-256: 10a1c07d93bf4917ca664632701e5154bb212d5a6452fcb62f6583c715f1776b

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

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 execute arbitrary commands or download additional payloads, although the specific commands are truncated in the provided evidence. This indicates a macro-based execution attack.

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.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `0d4ce61519ff44407ebc43be5794ea93ad4bc846efb9a73ee76933e168a67fb7`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	4569 bytes

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