Other Security Threats
In addition to the above threats, there are other common threats such as viruses, worms, spams, zombies and botnets that affect computers in a network and significantly impact overall network performance. All these threats are part of a software class called Malware (short for malicious software). Malware is designed to steal, damage, disrupt or commit other illegitimate actions on data, computers or networks.
Malware protection starts from your home network, and for better protection, you can change the password for your network router. Moreover, you should install and run a firewall on every computer that you use to prevent unauthorized access over the network.
Computer Viruses and Worms
A computer virus is a program that is loaded onto your computer without your knowledge. It has the potential to cause heavy damage to the computer. For example, it can cause annoying effects such as freezing your system, showing pop-ups, damaging data (deleting files) and software or even reformatting the hard disk. The virus can propagate by creating a functional copy of itself and spread across the network, thereby affecting all the computers that are connected to the network. It can also become part of another program and can also lead to a Denial of Service (DoS) condition.
A computer worm is a type of malware that can rapidly infect computers by replicating itself over the network. A worm creates functional copies of itself. However, unlike viruses, worms are standalone software and do not require a host program to propagate from one computer to another.
Security Solution: Install an antivirus suite on your computer that can protect against threats such as viruses and worms.
A Trojan horse is an impostor that contains malicious or harmful code. When the malicious code is triggered, it can lead to loss or theft of data. The Trojan horse does not replicate itself, as a virus does. It can spread using an email attachment. For a Trojan horse to spread, you must open an email attachment. In a network, a Trojan Horse can cause massive damage to all computers of that network.
Security Solution: Security suites such as Norton Internet Security help prevent you from downloading attachments that are likely to contain Trojan horses. All such attachments are scanned prior to downloading and the appropriate corrective action is taken instantly by the tool.
Spams generally refer to the junk emails that are sent to people without their permission. Mostly, they Contain advertisements for services or products. Most reputed companies do not use this method of advertising. A spam is also known as Unsolicited Commercial Email (UCE) or Unsolicited Bulk Email (UBE). Spams are less threating to network security but can be annoying for the users.
Security Solution: Spam filters can effectively be used to stop spam mails. Most email service providers are pre-equipped with spam filters that separate spam mails from your important mails and often store them in a separate folder. You can also purchase and install a variety of spam filters depending on your business requirement.
Phishing is a technique used to obtain personal information in a fraudulent manner. It is all about tricking people to give out their sensitive information such as credit card details and passwords. Emails that appear to be coming from a legitimate source are sent out under the name of a trustworthy company or website; asking the receiver to update their personal and financial information. This can lead to a huge financial loss or identify theft.
Security Solution: Phishing filters can be used to filter out these unwanted mails and to prevent this threat.
A packet sniffer is a device or software that allows eavesdropping on traffic moving between computers. It captures the data that is addressed to other machines and stores it for future analysis. This is one of the major security threats to a network. In a network, a packet sniffer can filter out personal information and this can lead to identity theft.
Security Solution: By using encryption, all packets become unreadable to anyone except the destination address, making the packet sniffers irrelevant.
Maliciously Coded Websites
Some websites contain malicious code. When you visit these websites, they can install Trojan Horses or redirect you to an unrequested and unsecure website. They (maliciously coded websites) are mainly designed to steal passwords, credit card numbers and other sensitive information.
Security Solution: Using a security suite such as AVG, we can detect infected sites and prevent the user from entering the site.
Zombies and Botnets
A zombie computer (also known as a bot) is a networked computer that has been infected by a computer virus or compromised by a hacker. The hacker takes complete control of the affected computer and performs malicious tasks remotely. In this way, hackers can take over large numbers of computers and create a network (called a botnet) connecting these computers. Now, all these computers can be controlled at once and used to perform malicious acts on a large scale. This is a major security threat on a network because the network, unknown to anyone, could be acting as a hub that forwards malicious files, etc. to other computers.
Security Solution: A good antivirus can help prevent zombie computers whereas a Network Intrusion Prevention (NIP) system can help prevent botnets. The best protection is to set your operating system, antivirus, anti-spyware and web browser programs to automatically look for latest updates and patches and install them whenever they are available.
Shared computers can have different risks such as unauthorised access and data privacy. You can take the following precautions to be safe when sharing computers:
- Never leave a computer unattended while you are logged in.
- Always sign out completely
- Clear the web browser cache
- Be careful of shoulder surfers
- Avoid confidential transactions
- Be wary of spyware
- Never save passwords
- Change your password frequently