Description

Detects usage of unencrypted Telnet connections through Python's telnetlib module. Telnet protocol transmits data including credentials in plaintext, making it vulnerable to network sniffing attacks and unauthorized access.

Detection Strategy

• Check if 'telnetlib' module is imported in the Python code

• Look for usage of 'telnetlib.Telnet' class or 'Telnet' after import

• Report vulnerability when Telnet connection creation is detected through these classes

Vulnerable code example

from telnetlib import Telnet

# VULNERABLE: Using Telnet which transmits credentials in cleartext
tn = Telnet("router.example.com", 23)
tn.write(b"admin\n")
tn.write(b"password\n")

✅ Secure code example

import paramiko

# SAFE: Using SSH instead of Telnet for encrypted communication
client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect('router.example.com', username='admin', password='password')

# Execute commands over secure SSH channel ...