Office (OOXML) / .XLSX malware analysis — malicious · 9ad54fe21026737b

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: 80a965f1f5b889db9d3368b9b9abc6e0 SHA-1: 5c71cf47874f340e7f11429bdf202202c5700093 SHA-256: 9ad54fe21026737bb876934163d8644c501d8f7fd056616a3ae17e4c9654a4d8

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 macro sheet content is heavily truncated and obfuscated, preventing a detailed analysis of its specific actions. However, the presence of Excel 4.0 macros strongly suggests an attempt to run arbitrary commands or download further payloads.

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` `294af49391877a66183742ff1743f4906fd4250689e947917369611a0e1626e6`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	629752 bytes

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