Most Dangerous Computer pc viruses and worms

Viruses and worms are a cause for thousands of losses all over the world. There are number of viruses and worms created. Below i have listed 6 most dangerous and havoc creating viruses that affected millions of computer users over the world. The order of viruses is not important.
Most dangerous computer viruses :

1. ILOVEYOU :

This ILOVEYOU worm is considered to be most dangerous worm ever created. It was written in VBScript. It was first noticed in Philippines on May 4 2000 and then spread all over world in just one day, affecting 10% internet users and causing loss of about $5.5 billion. The worm arrived in email inbox with subject “ILOVEYOU”. Hence, called ILOVEYOU worm. It had an attachment “LOVE-LETTER-FOR-YOU.TXT.vbs” . The worm overwrote many important files, with music, multimedia files with a copy of itself attached to each file. Also, it sent the worm to everyone on victim contact list. Thus, worm spread very fast. Only windows users were affected.

2. Mydoom :

Mydoom , a computer virus affected Microsoft Windows. After it was first noticed on January 26, 2004, it became fastest spreading computer virus ever, breaking record of Sobig worm. Mydoom was designed to send junk emails from infected computers. The actual worm programmer is still unknown.

3. Virut virus :

This Virut virus infects executable portable files such as .exe and .scr andeach time it propagates it uses Polymorphism - to evade detection. On infected machine, virus opens a backdoor connecting with an IRC server which is prespecified by virus programmer. This backdoor allow attacker to download additional malware to victim computer. This virus affected and shut down court system computers of Texas this February.

4. Blaster worm :

This Blaster worm - a computer worm that affected computers running Microsoft operating systems. But, the spread of this worm was limited by filtering of ISP and its publicity. The worm was designed to start a SYN Flood on Aug 15, 2003 against port 80 of windowsupdate.com, intended to create a distributed DDoS attack against this site.

If the worm detects an internet connection, the system would become unstable and after displaying a message for 60 seconds, the system used to restart. The message displayed looked like:

“I just want to say LOVE YOU SAN!!”
“billy gates why do you make this possible? Stop making money
and fix your software!!”

5. Sobig worm :

This worm ws detected in Aug 2003 which affected millions of internet connected windows operating systems. The worm was written using Microsoft Visual C++ compiler and compressed using tElock. The most destructive version was Sobig.F .

This worm was worm as it replicated itself and also a Trojan Horse as it appeared other than malware. The programmer of this worm is still not known.

6. Conficker virus :

This virus came into role in November 2008 and affected millions of computer. Basically, its a worm capable of replicating itself and thus can spread fast. The worm spreads itself primarily through a buffer overflow vulnerability in the Server Service on Windows based computers.

When this worm is executed on a computer, it is capable of disabling Windows services such as Windows Update, Windows Defender, Windows Security Center and even Windows Error reporting.

But, the threat due to this worm is reduced as most anti viruses are now detecting this worm and its further spread is thus prevented. This worm is mainly spreading in China, followed by Argentina, Brazil, Russia, and India - where software update is done to less extent.

So friends, this is all about viruses. These are most dangerous viruses or worms that affected millions of worldwide computers. I just wanted to say that keep your anti viruses updated to prevent yourself from being affected by such viruses and worms. If you think any other virus or worm needs mention over here, please mention it in comments section. I will update the article.

Source: http://computer-bloggingtricks.today.com/2009/03/12/6-ever-most-dangerous-computer-pc-viruses-and-worms/

Beware of viruses and parasites

By now, most computer users know that they have to protect against viruses. You need a good antivirus support program running on your computer in real time, monitoring and checking as files are accessed, as well as running periodic scans of all files. You need to use an up-to-date virus definition file with this AV program (sometimes these are updated almost every day, so automated updating is preferable). The virus protection on your computer should be so solid that there is rarely any doubt that you are virus-free — the only room for doubt being whether a new virus snuck in before your antivirus software’s manufacturer had a definition file that would catch it. If suspicious, run your AV program to check the system as part of zeroing in on a problem that suddenly develops on your computer. You can also try one or more of the free online virus scanners listed on my Parasites & Other Computer Security Issues page.

But there are also non viral invaders that have become as big a problem as viruses. In fact (perhaps because people are less aware of these and less mindful of protecting themselves), these parasites may be an even greater risk to your computer’s proper running. Adware, spyware, browser hijackers, automatic diallers, and other forms of non viral malware — some intentionally if misguidedly installed by the user, some foisted on you without your awareness — are, at least in a few cases, as destructive.

And, since they often are badly written, they commonly announce themselves unintentionally by breaking some functionality on the computer. Therefore, checking for these is an important early step in troubleshooting computer problems, especially if the problems appear suddenly. If there is a serious browser or Windows Explorer/My Computer problem not related to a bad or damaged browser install, failing hardware, or user error, 90% of the time the problem will be the result of one of these parasites. Because Internet Explorer is integrated into the kernel of all Windows versions after Win95, these “browser problems” can manifest as general performance degradation or error conditions in the Windows shell. If you’ve ruled out the obvious in troubleshooting browser failures, the eruption of many error messages, inability to launch programs, or sudden (in contrast to gradual) serious slowing of your computer, checking for parasites should probably be your next diagnostic step.

For an onderly seven-step approach for identifying and removing these parasitic invaders, see Quick Fix Protocol page.

Several of these parasites are intentionally added to the computer by the user because the program looks like a cool toy. For example, Hotbar is a popular browser add-on that causes big problems on most computers. Many people install Gator (now renamed Claria) to manage online passwords. People install the insidious and pernicious IEPlugin to get “faster, smarter web browsing,” and live to regret it. And so forth. Other parasites are snuck onto your computer often without your knowledge. An important early step in all troubleshooting of Windows problems, therefore, is the isolation and removal of such parasites.