Office (OOXML) / .XLSX malware analysis — malicious · 2951f52fa3475c72

MALICIOUS

Office (OOXML) / .XLSX

94.6 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 16.0300

MD5: 314cf76ce73e3f4fec65c25a808063e6 SHA-1: 8aedf59839916dfa014b991d5944cd513585b9af SHA-256: 2951f52fa3475c72c84bcf45f9320bc92df4827bf3de15aedbfc3bf8fcf3369e

120 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic for Applications

The file is an XLSX document containing embedded Excel 4.0 macros, identified by the OOXML_XLM_MACROSHEET and OOXML_XLSB_INTL_MACROSHEET_IN_XLSX heuristics. The extracted macro code contains references to 'ghenrope.rue', indicating it likely attempts to download a second-stage payload from this URL. The macro execution is the primary mechanism for this attack.

Heuristics 2

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.
XLSB international XLM macro sheet hidden in .xlsx critical OOXML_XLSB_INTL_MACROSHEET_IN_XLSX

OOXML package is named .xlsx but contains XLSB workbook parts and an international Excel 4.0 macro sheet. This hides XLM macro execution from scanners that trust the extension or only inspect XML worksheet parts. The technique is macro execution, not a document-parser CVE.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `1d86b3b52f2ca77e486b256d7c7d5bcd39881af7c02f6edc2a9373cc9635903a`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.bin	9817 bytes

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