Friday, January 3, 2014

Types Of Computer Viruses And Their Painful Effects



Through this post, I am gonna discuss about the types of computer viruses and its painful effects on PC. Hope it will help you to stay safe with your computer.
Now a days, the use of computer and internet has been rapidly increased. Together with it, the computer threats like spyware, Trojans and worms are rising and get into the action severely. So it is good to know the various types of computer viruses to protect your system from the malicious programs. Let me start discussion in my familiar writing style with a basic question.

What is computer virus?

A biological virus makes you sick! Like the same, computer virus infects your programs and files of your PC. Yes, it is an executable program which affects the normal operation of the computer by damaging the contents of the hard disk. It could cause frequent computer crashes, delete files, weakens computer memory and even reformatting the hard drive.

types-of-computer-viruses


How does computer viruses reach you?

Different types of computer viruses would reach you through the normal web activities like,
1. Opening email attachments from fake accounts.
2. Clicking inappropriate internet advertisements without understanding fully.
3. Installing/downloading the free games, tool-bars or system utilities.
4. Visiting an infected webpage
5. Setting up of software without license agreements and so on.
Not only with web activities, if you are not running the latest updates of your operating system and not using the good antivirus software, computer viruses would reach you easily.


Types of computer viruses

Many types of viruses are present and some popular viruses types are
1. Macro Virus
Macro virus is a type of email virus which mainly targets to infect the programs that contain Macros like Microsoft office files. These are mini programs which have the power to infect the template and document of that file.
2. Memory resident virus
Memory resident virus automatically fixes themselves in the computer memory and if the operating system started to run, it gets activated. It hideout in the computer memory and allocates space to execute its own code. It can easily corrupt the files which are recently used.
3. Multipartite Virus
Multipartite virus spreads in multiple ways and infects the programming files. They used to hide in the memory like Memory resident virus and do infect the hard disk.
4. Polymorphic Virus
Polymorphic virus are the powerful virus which might guards itself with encryption algorithm and has the tendency to change automatically when certain conditions are meet. Because of having encrypting capability, it is tough to find it by even with an antivirus program.
5. FAT virus
FAT virus spoils the file allocation system section (Information where the location of files and the details of the available spaces are stored) and might cause crucial damage to it. It would result in defeating the individual files or complete directories.
Not only these! There are still some common types of computer viruses like Web scripting viruses, Boot sector viruses, time/logic bombs, direct action viruses, Trojan horse virus, Root kits, spywares and worms have affinity to disrupts the computer operation.

Most dangerous computer viruses

In late 1980’s, computer viruses has started to born. Did you know about the first computer virus? It is “The Brain” released from Pakistan in the year 1986. So the 25th anniversary of the first PC virus was marked in 2011. The danger rating of the first computer virus is very low, but the most dangerous viruses came into existence in 1990’s. Let’s check some worst types of computer viruses now.
1. Code red
A powerful worm named “Code red” had made the anti-virus researchers in hindrance and it infected millions of computers and lakhs of servers. It took advantage in Microsoft internet information server too and was first detected by the employees of eEye digital security. It is not necessary to open an email attachment or execute a file, it catches your PC if you open a specific webpage.
2. Melissa
Melissa is a well-known worm which infected the MS word document files through email attachments using MS outlook. This virus caused a serious destruction to the computers in 1999 and the damage was estimated in millions of dollars. It had made the popular concerns like Intel and Microsoft temporarily to shut down.
3. My doom
My doom was considered a powerful virus in 2004 as it had the proficiency to stop accessing the antivirus program by the operating system. This virus spread through email with the text “Mail transaction failed” and gets downloaded into the system once the message got clicked. Millions of computers were infested through this virus and loss was estimated in billions.
4. Nimda
Nimda virus had risen in the year 2001 and it is just the reverse form of the word “Admin”. This virus targeted to slow down the internet traffic and it propagated to the system in different ways through emails, while sharing files, server weakness etc. Once this worm gets activated on the computer, the attacker would have the full control to the system if certain conditions are meet.
5. Conficker
Conficker is the widespread internet virus and so the anti-virus researchers called it as “Super worm”. Microsoft operating systems was targeted by this dangerous virus and so millions of computer which had vulnerable Windows OS had hit by it. This worst virus might spread through removable drives and assembled in such a way to take the financial and other vital data from the system.
If you’re are using computer from long, then you might be aware of some other worst types of viruses ike I love you (2000), Stuxnet (2009), agent.btz (2008), SQL Slammer (2003) and Blackworm (2006).

computer-viruses-types               Image credit: Flickr.com

Types of computer viruses in 2012

Now, do check some types of computer viruses which caused significant damage to the computers in the year 2012.
Shamoon
Shamoon was discovered in August 2012 that has been used for cyber spying. It infects the system runs on Windows NT, Windows me and Windows 9x. The attacker uses the “dropper” function to spread in the network to the hard disk of the computer so that to compile the list of files on attacked computers. Then the attacker receives the data with the help of “reporter” program. “Wiper” is the function used to erase the involved files and this might create problems in booting by overwriting action.
Gauss
Gauss is the highly destructive computer worm which was intentionally created to steal the data from Middle-east banks. It was discovered in June 2012 by a Russian lab and it affected thousands of computers. It can infect the USB drives and collected information will be stored as a hidden file on the removable drives.
DNS changer
Cyber-criminals created this virus to redirect the internet traffic to a phishing website. The DNS changer computer virus modified the Domain Name System (DNS) configuration of computers and redirects the users to a specific website. FBI got involved in this virus and the interim servers were official shutdown on July 9, 2012.
Belgian
Belgian is the worst computer virus spreads through spam emails or hacked webpages. It locked the computers and then asked for some money to unlock the data. This global virus has the power to gain the remote access to computers to track the files and launch the malware when Windows gets started.
Flame
Flame is the complex malware found in 2012 which used Bluetooth to send commands. It was discovered in Russian lab and it grabs the data from chats, emails and screenshots. It steal sensitive data and infects many computers in Iran and Middle east countries.
Many types of computer viruses are created everyday and the new computer virus like Ransomware (freezes the PC and ask to pay ransom to unlock) have started to cause damage to the computer this year. Even though the anti-virus researches are working to prevent these actions with powerful anti-virus software, cyber-criminals are tactically creating the malware.

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