Types of Computer Virus

Types of computer virus

Did you have face a problem with computer virus? I’m sure you are. Here I had search some article regarding types of computer virus that usual appear when we use a computer. Have a nice reading and please share this knowledge with your colleagues.

Trojans

Trojans, as in 'Trojan Horse', are a type of computer virus which can be installed on your computer without you realising. Trojans can install a ‘keystroke logger’, which records all the keys you press on your computer keyboard. Some try to capture passwords entered at certain web sites by capturing keystrokes or taking a picture of the screen. This information is then sent to the fraudsters.

Trojans are malicious programs which look innocent, fool you into accepting them, and then more or less take over your computer. You can go on using your PC or laptop while a criminal is also using it, remotely, for illegal purposes. Criminals have also designed programs called ‘rootkits’, which hide the fact that your computer has been compromised, so your antivirus software never spots the Trojan infection.

 Worms

These viruses are designed to cripple computer systems and networks. Once they’re out there, they don’t need to be sent – they’ll scan the internet themselves to find computers running specific programs that they can infect.

When it finds an IP address running the specific software, the worm attempts to infect the machine. Worms can be designed to infiltrate and damage corporate networks, spreading through network connections and corporate email systems.Worms can open ‘backdoors’ and give access to personal files and information, just as Trojans do, as well as damaging systems.

Email viruses

Email viruses can cause the same sort of damage as Trojans and worms. They use your email system to send themselves to every address they can find. So your friends or colleagues may receive an email from you with an attachment. When opened, the virus installs and, as well as causing malicious damage and exploiting security flaws, it will attempt to spread again using your friend’s email addresses. 

Botnets

Botnets, also known as zombie armies, are groups of computers on the internet, under the control of criminals. Each computer in the botnet has been infected by malicious software, but usually the owners have no idea, since the criminals control the computers remotely. Once your computer’s been compromised, it’s known as a bot (a software robot) or a zombie, and the criminal controlling it is a bot herder.Bot herders use botnets to carry out all kinds of criminal activities - to send email spam, to distribute malicious software (malware), to commit fraud and, of course, to infect more computers and make more botnets.

Between 50% and 80% of all spam is sent by zombie computers. This allows spammers to avoid detection and of course the owners of zombies pay for their internet connections too. This spam also furthers the spread of Trojan horses, malicious programs which allow criminals to take control of a computer.

 
Examples of botnets

Types of botnets include:

1. Denial of service attacks - Denial-of-service (DoS) attacks flood a website with thousands of simultaneous requests until the site crashes. Sometimes this might be done purely to cause mischief, but criminals also threaten companies with DoS attacks to extort payment from them.
2. Key logger - Some malware programs also install a key logger, which intercepts your keystrokes when you type a password, credit card number, or other personal information. This information is transmitted     to the criminal automatically and used for credit card fraud and other theft.
3. Banking Trojans - Banking Trojans infect your web browser and ‘piggy-back’ when you log in to your bank. They can then make or modify transactions that are invisible to both you and your bank.

 Source from : http://www.knowthenet.org.uk/knowledge-centre/viruses/types-computer-virus#sthash.JABd76ut.dpuf