TELNET

Telnet Protocol

Telnet - 23

• Telnet Server allows command line access to an embedded module over an IP network. Telnet is a protocol used on a network to provide a two-way interactive command line interface (CLI) using a virtual terminal connection. User data and Telnet control information is transferred on a data connection using TCP.
• The Default Port Number is 23.

1. Unencrypted Telnet Server:

Step 1: Open the command prompt and run the following “Nmap” script:

nmap –p23 --Script=telnet-encryption <target IP>

Step 2: The following screenshots show that the server is unencrypted:

2. The remote server runs on the cleartext protocols

Step1: Go to Terminal. Connect to the IP address by entering the following command:

telnet <target IP>

Step2: Then, enter the following username and password, as shown in the screenshots below,

User Name: admin

Password:

3. An adversary can login with default credentials:

Affected Ports:

• 23/tcp
• 80/tcp
• 443/tcp
• 9100/tcp
• 515/tcp
• 8443/tcp
• 8082/tcp

Case 1

Step 1: Open the “TELNET” tool and enter the following command in the Linux terminal:

telnet <target IP>

Step 2: Enter “admin” as username and “1234” as password.

Step 3: The following screenshot shows that the Telnet server can be accessed with the default credentials.

Case 2

Step 1: Enter the following URL in the Address bar of the browser:

https://<target IP>

Step 2: Enter “admin” as username and “1111” as password, as shown in the screenshot below.

Step 3: The following screenshot shows that the webpage can be accessed by using the default credentials.