Office (OOXML) / .XLSX malware analysis — malicious · 0e5d0dc5bda4a659

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: 0633683d4529f5e825e6919b1b41df1f SHA-1: 9f18ff80c743dcd5e7256a62ab67a9ac9c252a8e SHA-256: 0e5d0dc5bda4a6595bacb36ad14ccf28b44aa2ce853520aefbe90c658bc03c19

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The sample is an Excel file containing Excel 4.0 macros, indicated by the OOXML_XLM_MACROSHEET heuristic. These macros are capable of executing arbitrary commands, suggesting a malicious intent to run further payloads or perform unauthorized actions on the victim's system. The specific commands within the truncated macro sheet could not be fully analyzed.

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` `8186799a8459096a163aa948f25e6057373e025c9abc28431cd3014cb62246c8`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	287052 bytes

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