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Common Types of Malware
Malware is the collective word used to describe all types of Internet threats. These threats include, but are not restricted to, the following (click to find out more):
Computer Viruses
Up until just a few years ago, viruses were the main type of malware threatening computer systems. Even now, the majority of people tend to refer to malware as “viruses”, and any Internet security software as “antivirus”.
A virus is a type of software that has the ability to copy itself and infect a computer system without the user’s knowledge or permission. It got its name based on its similarities with biological viruses. Just like biological viruses get into the body and infect cells, computer viruses enter computers and infect files. Both types of viruses also reproduce themselves and spread by passing the infection from one system to another.
Viruses can enter a computer in many different ways, for example through email, downloading files, through different types of disks, or by simply surfing the Internet. Its effects can range from annoying to highly destructive.
Worms
Viruses are sometimes confused with computer worms and Trojan horses. To start with worms, this is a self-replicating computer program, which spreads by exploiting vulnerabilities in a computer’s operating system. The main difference between a virus and a worm is that a virus needs user intervention (e.g. starting a software program, or sending an email) to spread, while worms spread automatically by self-replication. In many cases, worm infections happen through email messages, making them easy to confuse with viruses.
Unlike a virus, a worm does not need to attach itself to an existing program, but can spread on its own, using a network to send copies of itself to other computer terminals on the network. It does not require any user intervention. While viruses almost always ruin or modify files on a targeted computer, worms generally cause harm to the entire network. The level of harm can range from only consuming bandwidth to something substantially more serious. Worm infections are always common but tend to increase significantly around special events and holidays such as Valentine’s Day, Christmas and Halloween.
Older worms were mainly written for Unix; however, the majority of today’s worms are written for Windows. Apart from that, worms tend to work in the same basic way today as they did in its earlier years. They scan a network for vulnerabilities, break into computers where they find this, and start self-replicating.
Spyware
Spyware is a type of malware that is designed to monitor a user’s interaction with the computer. However, despite its name, spyware does not stop there, but may in some cases take control over your computer in a similar manner as a Trojan horse can do. Spyware does not spread like viruses, but are generally installed by exploiting security holes or come packaged with user-installed software, for example peer-to-peer applications. Even though it defeats the purpose of the attack, spyware often tend to install so many processes that the infected computer becomes completely unusable.