10. Slammer (2003)
SQL Slammer is a worm that targets the weak database of Microsoft. The worm had taken advantage of the old security loophole of the server software. Once it becomes a part of the server, it starts sending fake data requests to various websites via attractive email. The existence of the virus was discovered in 2003 when it doubled its size every 8.5 seconds within a computer system. Slammer worm has infected over 75,000 hosts so far.
9. Sasser (2004)
In May 2004, computer experts dealt with four variations of worm that had damaged the Windows operating system. The worms were named as SasserA, SasserB,SasserC and SasserD. These had targeted Windows 2000, and other Windows operating system like Windows 95, Windows 98 and Windows XP and Windows ME. It spreads through emails that circulate in the net, and pretend to remove all the malware from the system. Another form of Sasser is known as Netsky-AC.
8. MyDoom (2004)
MyDoom is also called Novarg. This computer virus was first discovered in 2004. It had clogged networks, allowing unauthorized access to PC. The virus got spread to file sharing networks and was able to open “back door” to computer systems. Thousands of emails were sent in a couple of hours as the work was infecting the computers via Microsoft Windows platform.
7. Code Red (2001)
Code red damaged more than 222,000 computers all over the world. The infected websites showed message “Hacked by Chinese”. The goal of this virus is to get the strength of infected computers and attack their numerical internet addresses which represent the White House. But the timely preparations of this cyber attack were of great help and various such attacks were avoided.
6. Stuxnet (2010)
Stuxnet is another dangerous computer virus. It was discovered in July 2010. This worm targets computer systems that run critical infrastructure like water treatment, oil pipelines, gas pipelines and power grid etc. The virus infected over 43,000 systems, according to Symantec. About 15,000 computer systems in USA were infected, and about 20,000 in Iran due to this virus.
5. SirCam (2001)
SirCam is a sneaky computer bug. It had stolen sensitive information of various big websites. The virus also victimized even the former Ukraine President Leonid Kuchma. The sensitive files of the Ukrainian president included some of his personal information and project plans. The virus was first discovered in 2001. It was spread through opening the attached document in the emails, and became the reason of horrible results by damaging the computers instantly.
4. Klez.H (2002)
Klez.H first appeared in April 15, 2002. This virus had been infecting the computers through emails and fake internet connections. Several versions of this particular virus had been released in the cyberspace but the most hazardous is the Klez.H. This virus attacks the Windows, without impacting the Microsoft Outlook email system. An antivirus has been formed to deal with this dangerous virus.
3. Conficker (2008)
Conficker was spotted in November, 2008. The virus infects the computer systems all over the world through internet. Microsoft strongly suggested to the users to apply immediate updates to avoid this dangerous virus. In February 2009, this virus infected various machines, and Microsoft announced $250,000 as a reward to any information given about the creators of this virus.
2. iloveyou bug (2000)
The iloveyou bug was first found in Hong Kong in 2000. This virus had infected business and government computers. The antivirus companies across USA received various complaints from their affected customers. The virus mainly infected the United States Senate computer system, which was later on shut down to avoid any further problems. A Filipino computer student, Onel de Guzman, was the creator of the iloveyou bug.
1. Gameover Zeus (2014)
Gameover Zeus virus was discovered in June, 2014, by United States authorities who claimed that they were able to disrupt some of the most complex types of malware that was used for stealing millions of dollars online. This virus targets business websites, and has infected over 200,000 computer systems so far.
