Office (OOXML) / .XLSX malware analysis — malicious · bae2d7ac637ffb09

MALICIOUS

Office (OOXML) / .XLSX

87.9 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000

MD5: c34eec4129416c92cbbdd88ee611277b SHA-1: 48e7c63fec95144d7d5c0a1b491fe8df77bf86f4 SHA-256: bae2d7ac637ffb09620a20ff3acf68d21bb4a737f9fb99662f8943fad52701d3

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. These macros appear to be constructing a file path, 'C:\ProgramData\excel.rtf', which is highly suspicious and likely intended for dropping or executing a malicious payload. The macro execution itself is the primary attack vector here, aiming to run arbitrary commands.

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` `6fcfeb5c4fec8331ebe28eea210a9434972bc2e9cd2b3aff64226bd2105d9470`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	270346 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.