Netsky and Sasser – Netsky spread via e-mail and Windows networks, creating large amounts of Internet traffic and causing Denial of Service (DoS) attacks. At the time, Netsky and all its variants were believed to have accounted for as many as 25 percent of all computer viruses on the Internet. Sasser replicated by finding other systems with vulnerabilities and forcing them to download the virus. Once it was on a new machine, it altered the operating system to make it difficult for users to shut down their computer.
- Released in February and April 2004 respectively.
- Created by 17-year old Sven Jaschan.
- One of the few viruses to be tracked back to their creator.
SQL Slammer – A prolific web server virus, the Slammer (also known as Sapphire) infected nearly half of the servers that help run the Internet 15 minutes after its initial attack.
- Released in January 2003.
- Affected computer networks and systems, causing shutdowns and a range of damage estimated at over $1 billion.
- Caused Bank of America ATM service to crash, interruptions in Seattle’s 911 service, and more.
Nimda – Spreading through e-mail and Web pages, this worm targeted Internet servers, slowing Internet performance nearly to a halt. It also opened a backdoor to the computer’s operating system, allowing a hacker access to the computer. However, access was limited by user account permissions.
- Released in 2001.
- Name is the word “admin” spelled backward.
- Fastest spreading computer virus in history.
ILOVEYOU – Traveled through e-mail as a message from a secret admirer. When users downloaded the attachment called WIN-BUGSFIX.EXE, the virus would copy and embed itself in key files; including Registry keys.
- Suspected to have been created by Onel de Guzman (Philippines) in 2000.
- Initially spread through e-mail and later through IRC clients.
- Damage caused by the virus was estimated at around $10 billion.The original email virus, ILOVEYOU caused “massive estimated financial damage, with millions of computers infected,” according to Golden Richard III. The email masqueraded as a love letter from a contact in a user’s email address book, and prompted the user to open an attachment containing the virus. Beginning on March 4th, 2000, the virus infected over 50 million computers in only nine days, and caused the CIA and the Pentagon to shut down their computers.
Named after the Mountain Dew drink favored by the first researchers to analyze the program, this worm first broke out in July, 2001, infecting as many as 360,000 computers in a single day. According to Richard III, the infection proved so hard to stop because the worm would continually re-infect the same computer it had been cleaned from. The worm attacked Microsoft IS servers, and caused massive denial of service problems as it ate up computing resources and IT personnel time.
Conficker which is also known as Downup, Downadup, and Kido is a type of computer virus that usually targets Microsoft Windows Operating system. The virus was first identified in November 2008. This virus uses flaws of Windows operating system to fetch the administrator password via dictionary attacks while forming a botnet. This virus infected millions of computers which include government, business and home computer in over 190 countries.