Office (OOXML) / .XLSX malware analysis — malicious · d0612a840b76e5ff

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: c06c6ee414a336c05312fd01951e41c9 SHA-1: 7da75f9d17bde5b8b54a979d3f6b08fae8fa203e SHA-256: d0612a840b76e5ff85553fb1ba45daa9963cf027f4bbd3c842adb34d630e09c4

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The critical heuristic firing indicates the presence of Excel 4.0 macros within the XLSX file. While the macro content is truncated and heavily obfuscated, the presence of such macros strongly suggests an attempt to execute arbitrary code. The primary attack pattern is therefore macro-based execution.

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` `575a1f7d02ac292925080daaec38e56fe52573ea20071ba738b6a528498ae232`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	621056 bytes

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