Office (OOXML) / .XLSX malware analysis — malicious · 752e76b62d3dd852

MALICIOUS

Office (OOXML) / .XLSX

61.3 KB Created: 2021-03-14 20:07:32 UTC Authoring application: Microsoft Excel 16.0300

MD5: 9d400e455aa35dec498bffb77643cdef SHA-1: c32a408e13b4db2c1a82253b1d6ed16131acbd12 SHA-256: 752e76b62d3dd852a045c535d2cd0d1c6b47ef98e55526943738c221c933e166

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution

The critical heuristic firing indicates the presence of Excel 4.0 macros within the XLSX file. These macros are known to be used for executing arbitrary commands, often to download and execute further malicious stages. No specific family could be identified, and no direct IOCs like URLs or hashes were extracted from the macro content itself due to its truncated and obfuscated nature.

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` `9419d3d4d0b5c74f0a727ba07d353bb5847c2c09ac10a25d060a78e7e686fa6f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	95594 bytes

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