Office (OOXML) / .XLSX malware analysis — malicious · 0b841b6c25e00f18

MALICIOUS

Office (OOXML) / .XLSX

99.4 KB Created: 2021-03-29 19:55:06 UTC Authoring application: Microsoft Excel 16.0300

MD5: 44708eed04662f3da140978bee7345f7 SHA-1: e8b072a6faadf6e45804c53233284089520c0434 SHA-256: 0b841b6c25e00f18b0bf1b46762be9653bbb7e3477e043c94905acddd56bad58

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The file is an Excel spreadsheet containing Excel 4.0 macros. The heuristic firing indicates the presence of these macros, which are often used to execute malicious commands or download further payloads. The script content is heavily obfuscated and truncated, preventing a detailed analysis of its specific actions, but the presence of XLM macros strongly suggests an intent to execute arbitrary code.

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` `0d7587152bc0f528e5a96e63bf55d518f873054a6c56d73970556b76fed247db`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	94808 bytes

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