Computer viruses, Trojan horses, spyware and antivirus

As with medical viruses, computer viruses can be a draining and, frankly, annoying experience. You may be wondering what type of viruses exist, what they do and how they are transferred, or perhaps you simply want to know how best to avoid them. Broadband Buddy explores the murky world of computer germs.

What is a computer virus?

A computer virus is essentially a program written by a malicious author, with the intent of causing damage. Viruses are spread across the Internet by way of copying themselves, and, once activated, can perform a range of harmful acts – anything from causing slight start up or individual program problems to wiping your entire hard drive. According to the BBC, it’s estimated that a new virus is detected every 18 seconds, with prominent viruses causing billions of dollars worth of damage over the years. In all, there are thought to be millions of viruses in operation, and many more that have died out.

These days, viruses can be even more dangerous, not only compromising your computer’s safety but also your personal sensitive and personal information (such as credit card details). On a lesser note, your Internet surfing can be serious slowed down or hampered by a malicious bug. Without causing undue alarm, it is worth noting that many viruses that have been created in the previous year are not easily detected, if detectable at all. Although “antivirus” software exists (a program installed on your computer to monitor known viruses and check your computer hard drive for the presence of any), sometimes even such dedicated software can struggle to keep up with the vindictive Internet criminals. Viruses can be attached to normally safe webpages, downloaded to your computer and spread through your hard drive, despite “originating” from a trusted source. Sometimes a website may look normal (as the user would expect it to appear), but in actual fact it is a harmful website designed to fool the user for the purposes of (personal) “data mining” and credit card or ID fraud. This is particularly common with online banking sites and is known as “phishing”. You should be extra wary of phishing occurring through fraudulent spam emails, again, often looking like they have been sent from a reliable source, such as a bank or money transfer site, such as Pay Pal. Nevertheless, there are still ways to reduce risk.

Virus Symptoms

If you think that you might have a virus on your computer, these are some of the common symptoms:

• Unexpected deletion or absence of files and data from your hard drive
• Extreme slowing down of your computer
• Unusual noise from inside your computer
• Inability to access your hard drive
• Unexpected changing of filenames
• Distorted images and text on your screen

Damaging computer bugs

Malicious software, network-hijacking bugs and spying programs are things to be wary of in addition to viruses. Here are some of the main offenders currently in existence:

• File virus: program and file attacker

  These can replace system files on computers, and can spread easily to other sources from your computer outwards, either by way of disk, local area network (LAN) or the Internet. There are plenty of different types of these, with sub categories such as “Polymorphic Viruses”, “Stealth Viruses” and “Armored Viruses”.

• Trojan horse: stealth software enemy

  Named after the Trojan horse of Virgil's Latin epic poem “The Aeneid” (a giant wooden horse, apparently offered as a gift but in actual fact “hiding” an army of Greek soldiers ready to unleash war on the city of Troy), a Trojan virus is a program. Strictly speaking, this means that it is a far greater threat than a virus, installing damaging software, rather than simply inhibiting other programs. This software may allow access to your computer from uninvited (and dangerous) remote sources. Unlike other viruses, they don’t insert their code into other files to spread their own malicious content.

• Worm: network invader

  Also a slight variation on the virus (although the infamous “ILOVEYOU” bug was reported as one), worms spread easily over networks and the Internet. Unlike a virus, however, a worm does not need to attach itself to a program and can self-replicate and send copies of itself to other computers on a network, affecting the Internet and/or network by eating up bandwidth (the network’s capacity for transferring information) rather than actually damaging files.

• Spyware: behaviour and information voyeur

  Rather than damaging files, spyware generally slows your computer down over time. Spyware is most commonly installed, often unbeknownst to the novice user, along with other software (hence “spy”; also named so for the software’s objective to monitor a user’s activities). It is commonly downloaded alongside freeware or shareware and gathers information (through your Internet connection) without your knowledge, about your web habits and behaviour, often for advertising purposes.

Tips to Avoid and Contain Viruses

It is not just wise but essential to acquire a good antivirus software package. Trusted brands include Norton and McAfee, whilst GRISOFT’s free AVG program is a popular alternative to the sometimes expensive antivirus solutions. Some important tips to remember:

• Keep your anti-virus software up-to-date – always agree to suggestions of updating it
• Install a “firewall” – extra protection to monitor programs (and individuals) that have access to your computer, blocking entry to threats
• Use Windows, Apple and Linux (depending on your chosen platform) updates to patch security holes
• Don't open suspicious-looking email messages that look suspicious – apply common sense. If in doubt, it’s best to delete an email that contract a virus
• Avoid opening email attachments that you aren’t expecting, especially if the email and source look suspicious

If you think that you may already have a virus, either seek professional assistance or download some “search and destroy” software to hunt for potential threats within your system. It’s best, as a precaution, not to email others before you receive confirmation either way. As another option, you could consider switching to a Mac (or using Linux instead of Windows); PC’s are affected much more by viruses than Macs, party to due greater popularity of the platform, but some argue that Mac’s operating system is superior at repelling external attacks. Whichever system you use, ensure that you don’t shy away from the price of attaining secure antivirus protection – an afflicted computer can be extremely costly.