Reference no: EM133996815

Network Security Implementation

Securing the Router for Administrative Access

Objective
Securing the Router for Administrative Access

In this lab, you will perform the following tasks:

Task 1: Configure Basic Device Settings
Cable the network as shown in the topology.
Configure basic IP addressing for routers and PCs.
Configure OSPF routing.
Configure PC hosts.
Verify connectivity between hosts and routers.

Task 2: Control Administrative Access for Routers
Configure and encrypt all passwords.
Configure a login-warning banner.
Configure enhanced username password security.
Configure an SSH server on a router.
Configure an SSH client and verify connectivity.
Configure an SCP server on a router.

Background

The router is a critical component in any network. It controls the movement of data into and out of the network and between devices within the network. It is particularly important to protect network routers because the failure of a routing device could make sections of the network, or the entire network, inaccessible. Controlling access to routers and enabling reporting on routers is critical to network security and should be part of a comprehensive security policy. No AI shortcuts — Only authentic assignment help from real expert tutors.

In this lab, you will build a multi-router network and configure the routers and hosts. Use various CLI tools to secure local and remote access to the routers, analyze potential vulnerabilities, and take steps to mitigate them. Enable management reporting to monitor router configuration changes.
Note: Before beginning, ensure that the routers and switches have been erased and have no startup configurations.

Task 2: Control Administrative Access for Routers
Configure and encrypt passwords.
Configure a login-warning banner.
Configure enhanced username password security.
Configure enhanced virtual login security.
Configure an SSH server on R1-STUDENTID-STUDENTID.
Research terminal emulation client software and configure the SSH client.
Configure an SCP server on R1-STUDENTID-STUDENTID.
Note: Perform all tasks on both R1-STUDENTID-STUDENTID and R3-STUDENTID. The procedures and output for R1-STUDENTID are shown here.
Step 1: Configure and Encrypt Passwords on Routers R1-STUDENTID and R3-STUDENTID.
Configure a minimum password length for all router passwords.
Use the security passwords command to set a minimum password length of 10 characters. R1-S0000# conf t
R1-S0000(config)# security passwords min-length 10

R2-S0000# conf t
R2-S0000(config)# security passwords min-length 10

R1-S0000# conf t
R3-S0000(config)# security passwords min-length 10
Configure the enable secret password.
Configure the enable secret encrypted password on both routers. Use the type 9 (SCRYPT) hashing algorithm. R1-S0000(config)# enable secret cisco12345
How does configuring an enable secret password help to protect a router from being compromised by an attack?

Configure basic console, auxiliary port, and virtual access lines.
Note: Passwords in this task are set to a minimum of 10 characters but are relatively simple for the benefit of performing the lab. More complex passwords are recommended in a production network.
Configure a console password and enable login for routers. For additional security, the exec-timeout command causes the line to log out after 5 minutes of inactivity. The logging synchronous command prevents console messages from interrupting command entry.
Note: To avoid repetitive logins during this lab, the exec-timeout command can be set to 0 0, which prevents it from expiring. However, this is not considered a good security practice.
R1-S0000# conf t
R1-S0000(config)# line console 0
R1-S0000(config-line)# password ciscocon R1-S0000(config-line)# exec-timeout 5 0 R1-S0000(config-line)# login
R1-S0000(config-line)# logging synchronous
When you configured the password for the console line, what message was displayed?

Configure a new password of ciscoconpass for the console.
Configure a password for the AUX port for router R1-STUDENTID. R1-S0000(config)# line aux 0
R1-S0000(config-line)# password ciscoauxpass R1-S0000(config-line)# exec-timeout 5 0
R1-S0000(config-line)# login
Telnet from R2-STUDENTID to R1-STUDENTID.

R2-S0000> telnet 10.1.1.1
Were you able to login? Explain.

What messages were displayed?

Configure the password on the vty lines for router R1-STUDENTID. R1-S0000(config)# line vty 0 4
R1-S0000(config-line)# password ciscovtypass R1-S0000(config-line)# exec-timeout 5 0
R1-S0000(config-line)# transport input telnet R1-S0000(config-line)# login
Note: The default for vty lines is now transport input none.
Telnet from R2-STUDENTID to R1-STUDENTID again. Were you able to login this time?

Enter privileged EXEC mode and issue the show run command. Can you read the enable secret password? Explain.

Can you read the console, aux, and vty passwords? Explain.

g. Repeat the configuration portion of steps 3a through 3g on router R3-STUDENTID.

Encrypt clear text passwords.
Use the service password-encryption command to encrypt the console, aux, and vty passwords.

R1-S0000(config)# service password-encryption
Issue the show run command. Can you read the console, aux, and vty passwords? Explain.

At what level (number) is the default enable secret password encrypted?
At what level (number) are the other passwords encrypted?
Which level of encryption is harder to crack and why?

Step 2: Configure a Login Warning Banner on Routers R1-STUDENTID and R3-STUDENTID.
Configure a warning message to display prior to login.
Configure a warning to unauthorized users with a message-of-the-day (MOTD) banner using the banner motd command. When a user connects to one of the routers, the MOTD banner appears before the login prompt. In this example, the dollar sign ($) is used to start and end the message.
R1-S0000(config)# banner motd $Unauthorized access strictly prohibited!$ R1-S0000(config)# exit
Issue the show run command. What does the $ convert to in the output?

Configure Banner on R2-STUDENTID and R3-STUDENTID?

Step 3: Configure Enhanced Username Password Security on Routers R1-STUDENTID and R3-STUDENTID.
Investigate the options for the username command.
In global configuration mode, enter the following command: R1-S0000(config)# username user01?
What options are available?

Create a new user account with a secret password.
Create a new user account with SCRYPT hashing to encrypt the password.
R1-S0000(config)# username user01 secret user01pass
Exit global configuration mode and save your configuration.
Display the running configuration. Which hashing method is used for the password?

Test the new account by logging in to the console.
Set the console line to use the locally defined login accounts.
R1-S0000(config)# line console 0 R1-S0000(config-line)# login local R1-S0000(config-line)# end
R1-S0000# exit
Exit to the initial router screen which displays: R1-STUDENTID con0 is now available, Press RETURN to get started.
Log in using the previously defined username user01 and the password user01pass.
What is the difference between logging in at the console now and previously?

After logging in, issue the show run command. Were you able to issue the command? Explain.

Enter privileged EXEC mode using the enable command. Were you prompted for a password? Explain.

Test the new account by logging in from a Telnet session.
a. From Router2-STUDENTID, establish a Telnet session with R1-STUDENTID. Telnet is disabled by default in Windows 7. If necessary, search online for the steps to enable Telnet in Windows 7.
R2-S0000# telnet 192.168.1.1
Were you prompted for a user account? Explain.

Set the vty lines to use the locally defined login accounts. R1-S0000(config)# line vty 0 4
R1-S0000(config-line)# login local
From Router2-STUDENTID, telnet to R1-STUDENTID again.
R2-S0000# telnet 192.168.1.1
Were you prompted for a user account? Explain.

Log in as user01 with a password of user01pass.
During the Telnet session to R1-STUDENTID, access privileged EXEC mode with the enable command.
What password did you use?

For added security, set the AUX port to use the locally defined login accounts.
R1-S0000(config)# line aux 0
R1-S0000(config-line)# login local
End the Telnet session with the exit command.

Step 4: Configure the SSH Server on Router R1-STUDENTID and R3-STUDENTID.

In this task, use the CLI to configure the router to be managed securely using SSH instead of Telnet. Secure Shell (SSH) is a network protocol that establishes a secure terminal emulation connection to a router or other networking device. SSH encrypts all information that passes over the network link and provides authentication of the remote computer. SSH is rapidly replacing Telnet as the remote login tool of choice for network professionals.

Note: For a router to support SSH, it must be configured with local authentication, (AAA services, or username) or password authentication. In this task, you configure an SSH username and local authentication.
Configure a domain name.
Enter global configuration mode and set the domain name.
R1-S0000# conf t
R1-S0000(config)# ip domain-name ccnasecurity.com
Configure a privileged user for login from the SSH client.
Use the username command to create the user ID with the highest possible privilege level and a secret password.
R1-S0000(config)# username admin privilege 15 secret cisco12345
Note: Usernames are not case sensitive by default. You will learn how to make usernames case sensitive.
Exit to the initial router login screen. Log in with the username admin and the associated password. What was the router prompt after you entered the password?

Configure the incoming vty lines.
Specify a privilege level of 15 so that a user with the highest privilege level (15) will default to privileged EXEC mode when accessing the vty lines. Other users will default to user EXEC mode. Use the local user accounts for mandatory login and validation and accept only SSH connections.
R1-S0000(config)# line vty 0 4
R1-S0000(config-line)# privilege level 15 R1-S0000(config-line)# login local
R1-S0000(config-line)# transport input ssh R1-S0000(config-line)# exit
Note: The login local command should have been configured in a previous step. It is included here to provide all commands, if you are doing this for the first time.

Note: If you add the keyword telnet to the transport input command, users can log in using Telnet as well as SSH, however, the router will be less secure. If only SSH is specified, the connecting host must have an SSH client installed.
Erase existing key pairs on the router.
R1-S0000(config)# crypto key zeroize rsa
Note: If no keys exist, you might receive this message: % No Signature RSA Keys found in configuration.
Generate the RSA encryption key pair for the router.
The router uses the RSA key pair for authentication and encryption of transmitted SSH data.
Configure the RSA keys with 1024 for the number of modulus bits. The default is 512, and the range is from 360 to 2048.
R1-S0000(config)# crypto key generate rsa general-keys modulus 1024 The name for the keys will be: R1-STUDENTID.ccnasecurity.com
% The key modulus size is 1024 bits
% Generating 1024 bit RSA keys, keys will be non-exportable...[OK] R1-S0000(config)#
*Dec 16 21:24:16.175: %SSH-5-ENABLED: SSH 1.99 has been enabled
Issue the ip ssh version 2 command to force the use of SSH version 2.
R1-S0000(config)# ip ssh version 2 R1-S0000(config)# exit
Note: The details of encryption methods later.
Verify the SSH configuration.
Use the show ip ssh command to see the current settings.
R1-S0000# show ip ssh
Fill in the following information based on the output of the show ip ssh command.
SSH version enabled:
Authentication timeout:
Authentication retries:

Configure SSH timeouts and authentication parameters.
The default SSH timeouts and authentication parameters can be altered to be more restrictive using the following commands.
R1-S0000(config)# ip ssh time-out 90
R1-S0000(config)# ip ssh authentication-retries 2
Save the running-config to the startup-config.
R1-S0000# copy running-config startup-config