A computer virus is a malware program that, when executed, replicates by inserting copies of itself into other computer programs, data files, or the boot sector of the hard drive; when this replication succeeds, the affected areas are then said to be "infected".Viruses often perform some type of harmful activity on infected hosts, such as stealing hard disk space or CPU time, accessing private information, corrupting data, displaying political or humorous messages on the user's screen, spamming their contacts, or logging their keystrokes. However, not all viruses carry a destructive payload or attempt to hide themselves—the defining characteristic of viruses is that they are self-replicating computer programs which install themselves without the user's consentAll computer viruses are man-made. A simple virus that can make a copy of itself over and over again is relatively easy to produce. Even such a simple virus is dangerous because it will quickly use all available memory and bring the system to a halt. Here are the10 most famous and malicious computer viruses.-------
1.Gameover Zeus
Zeus is a Trojan horse made to infect Windows computers so that it will perform various criminal tasks. The most common of these tasks are usually man-in-the-browser keylogging and form grabbing. The majority of computers were infected either through drive-by downloads or phishing scams. First identified in 2009, it managed to compromise thousands of FTP accounts and computers from large multinational corporations and banks such as Amazon, Oracle, Bank of America, Cisco, etc. Controllers of the Zeus botnet used it to steal the login credentials of social network, email and banking accounts.
2.Code Red
Code red had infected over 225,000 computer systems worldwide in which sites that were affected had displayed messages of “Hacked by Chinese”. But despite the message, the exact origin of the virus was unclear.Ultimate goal of the worm was to gather strength by infecting pc and let those computers attack a numerical internet address which represented the White House.
3.iloveyou bug
The iloveyou bug was first spotted in Hong Kong and it had spread gradually to the west. It had infected business and government computers. Anti-virus companies in U.S had received many calls from their affected customers which had reported widespread infections Many had fallen to the iloveyou bug because they had received an e-mail in which a “love letter” was attached. In the file, a Visual Basic script which has the virus payload. When the attached e-mail is opened, the computer will then be infected and it will spread by sending itself again to another e-mail and it will be send unknowingly to another e-mail user in the address book.
4.Stuxnet
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. It was estimated that Stuxnet has managed to ruin one fifth of Iran’s nuclear centrifuges and that nearly 60% of infections were concentrated in Iran.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.
5.CryptoLocker
CryptoLocker is a form of Trojan horse ransomware targeted at computers running Windows. It uses several methods to spread itself, such as email, and once a computer is infected, it will proceed to encrypt certain files on the hard drive and any mounted storage connected to it with RSA public key cryptography. While it is easy enough to remove the malware from the computer, the files will still remain encrypted. The only way to unlock the files is to pay a ransom by a deadline. If the deadline is not met, the ransom will increase significantly or the decryption keys deleted. The ransom usually amount to $400 in prepaid cash or bitcoin.
6.Flashback
Though not as damaging as the rest of the malware on this list, this is one of the few Mac malware to have gain notoriety as it showed that Macs are not immune. The Trojan was first discovered in 2011 by antivirus company Intego as a fake Flash install. In its newer incarnation, a user simply needs to have Java enabled (which is likely the majority of us). It propagates itself by using compromised websites containing JavaScript code that will download the payload. Once installed, the Mac becomes part of a botnet of other infected Macs.
7.Sasser
A Windows worm first discovered in 2004, it was created by computer science student Sven Jaschan, who also created the Netsky worm. While the payload itself may be seen as simply annoying (it slows down and crashes the computer, while making it hard to reset without cutting the power), the effects were incredibly disruptive, with millions of computers being infected, and important, critical infrastructure affected. The worm took advantage of a buffer overflow vulnerability in Local Security Authority Subsystem Service (LSASS), which controls the security policy of local accounts causing crashes to the computer. It will also use the system resources to propagate itself to other machines through the Internet and infect others automatically.
8.Melissa
Named after an exotic dancer from Florida, it was created by David L. Smith in 1999. It started as an infected Word document that was posted up on the alt.sex usenet group, claiming to be a list of passwords for pornographic sites. This got people curious and when it was downloaded and opened, it would trigger the macro inside and unleash its payload. The virus will mail itself to the top 50 people in the user’s email address book and this caused an increase of email traffic, disrupting the email services of governments and corporations. It also sometimes corrupted documents by inserting a Simpsons reference into them.
9.MyDoom
Surfacing in 2004, Mydoom was a worm for Windows that became one of the fastest spreading email worm since ILOVEYOU. The author is unknown and it is believed that the creator was paid to create it since it contains the text message, “andy; I’m just doing my job, nothing personal, sorry,”. It was named by McAfee employee Craig Schmugar, one of the people who had originally discovered it. ‘mydom’ was a line of text in the program’s code (my domain) and sensing this was going to be big, added ‘doom’ into it.
10.Conficker
Conficker was spotted in November 21, 2008, the worm can infect other computers across a network and it can fix the bug as other worms trying the same are locked out. The next day, Microsoft had strongly suggested to its users to apply immediate updates to counteract vulnerabilities however, machines that were infected with Conficker A were activated. It then started to use different sets of 250 domains every day for other instructions. At that time, 500,000 computers are already thought to be infected with this worm.
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Unknown - Sabtu, 07 Februari 2015 - 18.00
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