Securing Network Connections

Home Network

• Files and documents
• An Internet connection
• Printers and scanners
• Stereos, TVs, and game systems
• DVD/CD burners

Network Devices

• Wireless communications hardware that creates a central point of wireless connectivity

• Any device that connects different network environments

• Network device that has both transmitter and receiver components

• Used to connect one network device to other devices

• Hardware devices used to enter data into a computer or to display data from the computer

• Devices that can connect several network devices

• Used to connect all segments of a network

• Used to connect several types of cables within an existing network

• Used to physically connect a computer to a network

• to be transmitted across an analog network medium and then back to digital at the receiving end

Wireless Networks

• Wireless networks are used to connect the computers to each other without any cables.
• They have become popular due to ease of installation and the increasing popularity of laptops and smartphones.
• Restaurants, hotels, business centers, apartment complexes, and
  individuals often provide wireless access with little or no protection.
• Service Set Identifier (SSID) is the name of the network.
• All devices on the wireless network must use the same SSID to communicate with each other.

Securing Wireless Networks

1. Enable MAC Address filtering to keep track of all network MAC devices connecting to the router.
2. Data transmitting over wireless networks should be encrypted to prevent eavesdropping, interception, and data modification.
3. Network level denial of service attacks are prevented by using user authentication.
4. Unauthenticated access to the wireless network can be prevented by using VPN connection and IPsec.
5. VPNs keep the communications safe by creating secure tunnels through which the encrypted data travels.
6. A network should be scanned using software scanning tools to locate and shut down rogue WLANs.
7. If the user is connected to an unprotected wireless network at
   public places, do not visit a website that requires a password unless
   the website is encrypted.

Sharing on Networks

• Read
• Modify
• Copy
• Print

1. Default share
• Does not provide security
• Requires no configuration
• Requires share designation
2. Restricted share
• Provides security by limiting the number of users accessing the share at a particular time
• Designates specific users to access the share
• Allots permissions to control user activity on the share (offline/online)

Network Security Threats

1. Malware:
• Email, instant messaging, and file sharing programs have
  traditionally been used to spread viruses, worms, backdoors, rootkits,
  Trojans, and spyware from computer to computer
2. Sniffing:
• Unsecured network connections such as WiFi access points are used by hackers to set up packet sniffers to monitor all traffic that comes and goes to a network
3. Denial of Service:
• Denial of service causes the computer to crash or to become so busy processing data that you cannot use it
4. Mobile code (Java, JavaScript, and ActiveX):
• Intruders use mobile code to gather information such as the websites visited or to run malicious code on your computer
5. Email spoofing:
• An email message appears to have originated from one source when it
  actually was sent from another source to trick the user to expose
  sensitive information
6. Chat clients:
• Chat clients allow the exchange of executable code that may be malicious
7. Being an intermediary for another attack:
• Intruders use compromised computers as launching pads for attacking other systems
8. Back door and remote administration programs:
• BackOrifice, Netbus, and SubSeven are the tools commonly used by intruders to attack Windows computers
9. Cross‐site scripting:
• A malicious web developer may attach a script to something sent to a website, such as a URL that is transferred to your browser when the
  website responds to you
10. Unprotected Windows shares:
• Unprotected Windows networking shares can be exploited by intruders
  to place distributed attack tools of Windows‐based computers connected
  to the Internet

Firewalls

• It controls traffic coming into and leaving the system by permitting authorized communications.
• It hides the user’s home network from the outside world.
• It can be either a hardware or software.
• Personal firewalls are recommended on all computers.
• It monitors all the requests coming into the system, alerts the user, and asks permission for allowing/blocking them.

Network Security Checklist

• Schedule regular backups of the data files
• Change network device passwords regularly
• Regularly update the operating system and other software with the latest patches
• Block all access to the network infrastructure from the outside
• Run performance monitoring software to receive alerts if something abnormal happens on the servers or the network
• Install antivirus software on all workstations
• Configure servers to scan both incoming and outgoing files
• Scan all incoming and outgoing email and attachments