Office (OOXML) / .XLSX malware analysis — malicious · 945de16b7780b22c

MALICIOUS

Office (OOXML) / .XLSX

135.6 KB Created: 2021-08-16 09:36:27 UTC Authoring application: Microsoft Excel 12.0000

MD5: 11f8f9028c6f5be72efde75cd177515e SHA-1: 35ff2216c6e7b1bb89bcd2299f4a8062a713f434 SHA-256: 945de16b7780b22c96087724a576577b397716a1731dc2e540bce2f21f07c175

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The file is an Excel spreadsheet containing Excel 4.0 macros, which is a known technique for executing malicious code. The macros are heavily obfuscated, making it difficult to determine the exact payload or execution flow. However, the presence of these macros strongly suggests an intent to run arbitrary commands on the user's system.

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` `7f8920051de3b4fc7e16559ed5e1405e9969593a7d4476da8087f9f70e1bf933`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	619373 bytes

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