Network Attacks and Defenses

Router Security  ◾  293

8.3.5.3 Step 3: Sniff Telnet Traffic

To configure Telnet authentication credentials, create a local

database and assign it to the login service of the VTY (Telnet)

line by entering the following commands:

Telnet 192.168.1.1 (router) from the PC to generate Telnet traffic

using Microsoft built-in Telnet client.

Once the user Access Verification window appears, enter the

username as “CIT” and the password as “CISCO”, as config-

ured previously.

Sniff the Telnet packets on port 23. As demonstrated in

the following series of screenshots, the Telnet traffic is not

encrypted. By analyzing the traffic, it is easy to capture the

Telnet