Top 10 computer viruses 2013

The Pentagon, the CIA, and the British Parliament all had to shut down their e-mail systems in order to purge the threat. Conficker -- The Conficker worm has created a secure, worldwide infrastructure for cybercrime. The worm allows its creators to remotely install software on infected machines. What will that software do?

We don't know. Most likely the worm will be used to create a botnet that will be rented out to criminals who want to send SPAM, steal IDs and direct users to online scams and phishing sites. Melissa -- Melissa was an exotic dancer, and David L. Smith was obsessed with her and also with writing viruses. The virus he named after Melissa and released to the world on March 26, , kicked off a period of high-profile threats that rocked the Internet between and Slammer -- This fast-moving worm managed to temporarily bring much of the Internet to its knees in January The threat was so aggressive that it was mistaken by some countries to be an organized attack against them.

The entire operation was sophisticated, involving people from around the world to act as money mules to smuggle and transfer cash to the ringleaders in Eastern Europe. In late , the creator of Zeus announced his retirement but many experts believe this to be false.

Also known as Downup or Downadup , Conficker is a worm of unknown authorship for Windows that made its first appearance in The name comes form the English word, configure and a German pejorative. It infects computers using flaws in the OS to create a botnet. The malware was able to infect more than 9 millions computers all around the world, affecting governments, businesses and individuals.

The worm works by exploiting a network service vulnerability that was present and unpatched in Windows. Once infected, the worm will then reset account lockout policies, block access to Windows update and antivirus sites, turn off certain services and lock out user accounts among many. Then, it proceeds to install software that will turn the computer into a botnet slave and scareware to scam money off the user.

Microsoft later provided a fix and patch with many antivirus vendors providing updates to their definitions. Believed to have been created by the Israeli Defence Force together with the American Government, Stuxnet is an example of a virus created for the purpose of cyberwarfare , as it was intended to disrupt the nuclear efforts of the Iranians.

The computer worm was designed to attack industrial Programmable Logic Controllers PLC , which allows for automation of processes in machinery. It specifically aimed at those created by Siemens and was spread through infected USB drives. It altered the speed of the machinery, causing it to tear apart. Siemens eventually found a way to remove the malware from their software.

It was named by McAfee employee Craig Schmugar, one of the people who had originally discovered it. The worm spreads itself by appearing as an email transmission error and contains an attachment of itself. The payload itself is twofold: first it opens up a backdoor to allow remote access and second it launches a denial of service attack on the controversial SCO Group.

It was believed that the worm was created to disrupt SCO due to conflict over ownership of some Linux code. If earlier worms, like Code Red see below , were about mischief, Fizzer was all about money.

Slammer works by releasing a deluge of network packets, units of data transmitted over the Internet, bringing the Internet on many servers to a near screeching halt. Through a classic denial of service attack, Slammer had a quite real effect on key services. But when it swept across computers worldwide in , it caught security experts off guard by exploiting a flaw in Microsoft Internet Information Server. That allowed the worm to deface and take down some websites.

Perhaps most memorably, Code Red successfully brought down the whitehouse. Other names may be trademarks of their respective owners. Internet Security Centre. Norton UK Blog. CryptoLocker When it comes to malware, ransomware is the new kid on the block.

But why was it so brutal? Source: Shutterstock Well, in malware was a bit of a myth. MyDoom MyDoom is considered to be the most damaging virus ever released—and with a name like MyDoom would you expect anything less? Tip: never open a link in an email unless you know exactly what it is. Cost of the malware: An exact cost is yet to be calculated. Slammer While most of the malware on this list strictly hit computers, Slammer was created with broader ambitions.

Source: Stocksnap 8. Stuxnet Stuxnet is easily the scariest virus on the list as it was built by government engineers in the US with the intention of obstructing nukes from being built in Iran. Yes, you read that right. Who needs to target email when they can gun for nukes?

Cost of the malware: Unknown. Opt-in to Cyber Safety. Read all reviews. Watch the TV ad. Norton Deluxe.