Threats to Computer Security (Virus)

Threats to Computer Security (Virus)

The words Trojan, worm and virus are often used interchangeably, though they are not exactly the same thing. Viruses, worms and Trojan horses are all malicious programs that can cause damage to our computer.

Virus

It is a malicious computer program and attaches itself to a program or file, enabling it to spread from one computer to another. Like a human virus, some computer viruses may cause only mildly annoying effects while others can damage your hardware, software or files. Almost all viruses are attached to an executable file, which means the virus may exist on your computer but it actually cannot infect your computer unless you run or open the malicious program. It is important to note that a virus cannot be spread without a human action (such as running an infected program) to keep it going. As a virus is spread by human action people will unknowingly continue the spread of a computer virus by sharing infecting files or sending emails with viruses as attachments in the email.

Worm

It is similar to a virus by design and is considered to be a sub-class of a virus. Worms spread from computer to computer, but, unlike a virus, it has the capability to travel without any human action. A worm takes advantage of file or information transport features on your system, which is what allows it to travel unaided. The biggest danger with a worm is its capability to replicate itself on your system, so rather than your computer sending out a single worm, it could send out hundreds or thousands of copies of itself, creating a huge devastating effect. One example would be for a worm to send a copy of itself to everyone listed in your e-mail address book. Then, the worm replicates and sends itself out to everyone listed in each of the receiver’s address book, and the manifest continues on down the line.

Due to the copying nature of a worm and its capability to travel across networks, the end result in most cases is that the worm consumes too much system memory (or network bandwidth), causing Web servers, network servers and individual computers to stop responding.

Trojan horse

It is as tricky as the mythological Trojan horse it was named after. At first glance it will appear to be useful software but will actually do damage once installed or run on your computer. Those on the receiving end of a Trojan horse are usually tricked into opening them because they appear to be receiving legitimate software or files from a legitimate source.  Some Trojans are designed to be more annoying than malicious (like changing your desktop, adding silly active desktop icons) or they can cause serious damage by deleting files and destroying information on your system. Trojans are also known to create a backdoor on your computer that gives malicious users access to your system, possibly allowing confidential or personal information to be compromised. Unlike viruses and worms, Trojans do not reproduce by infecting other files; nor do they self-replicate.

Blended Threats

A blended threat is a more sophisticated attack that bundles some of the worst aspects of viruses, worms, Trojan horses and malicious code into one single threat. Blended threats can use server and Internet vulnerabilities to initiate, then transmit and also spread an attack. Characteristics of blended threats are that they cause harm to the infected system or network, they propagate using multiple methods, the attack can come from multiple points, and blended threats also exploit vulnerabilities. While a worm may travel and spread through e-mail, a single blended threat could use multiple routes, including e-mail, IRC and file-sharing networks. Blended threats are considered to be the worst risk to security since the inception of viruses, as most blended threats also require no human intervention to propagate.

Combating Viruses, Worms and Trojan Horses

The first step in protecting your computer from any malicious programme is to ensure that your operating system (OS) is up to date. Secondly, you need to have anti-virus software installed on your system and ensure you download updates frequently to ensure your software has the latest fixes for new viruses, worms, and Trojan horses. Additionally, you want to make sure your anti-virus program has the capability to scan e-mail and files as they are downloaded from the Internet, and you also need to run full disk scans periodically. This will help prevent malicious programs from even reaching your computer.

Firewall

A firewall is a system that prevents unauthorised use and access to your computer. A firewall can be either hardware or software. Hardware firewalls provide a strong degree of protection from most forms of attack coming from the outside world and can be purchased as a stand-alone product or in broadband routers. Unfortunately, when battling viruses, worms and Trojans, a hardware firewall may be less effective than a software firewall, as it could possibly ignore embedded worms in outgoing e-mails and see this as regular network traffic.

For individual home users, the most popular firewall choice is a software firewall. The downside to software firewalls is that they will only protect the computer they are installed on, not a network.

........