A virus is are caracterized because of causing different types of errors and damages in the computer.
Now, I´m going to explain you the top 5 of the worst viruses in the history:
1- My Doom: My Doom explored its way to the malware world on 26th January 2004 and sent a shockwavearound the world as it scattered exponentially via e-mail with random servers´addresses and subject lines. It is also knows as Novarg.
2- Iloveyou: back in 2000, is one of the trickiest computer malware ever was detected on May 4 in Philippines. The virus was transmitted via e-mail having a subject line "ILOVEYOU". As soon as it was open the virus send it to the first 50 contacts on Windows.
3- Sobig F: August 2003 turned out to be the miserable month for corporate and domestic computer operators around the world as the six and most destructive deviant of Sobig series hit the Internet. Sobig F infected host computer by fooling the users that the corrupt e-mail they receive is from a legimitate source. If the user opens the attachment it exposes a security hole in the system allowing the intruder to send messages via the trapped user´s e.mail address.
4- Code red: in 2001, acomputer worm was unleashedon the networks server. The interesting thing about this, was that you needn´t have to open the the -mail attachment. It only needs an active internet connection with which it defaces the webpage you open and display a text string "Hacked by Chinese!"
5.- SQL Slammer: it appeared in 2003. It mainly targeted on the servers by generating random Ip addresses and discharging the worm to those Ip addresses. The abrupt release of infected network packets had huge impact on the significant services provided by Bank of America´s ATMs, Seattle´s 911 emergency response systems and Continental airlines.
The first computer viruses:
- Elk Cloner was the first personal computer virus to appear outside the single computer or lab where it was created. It attached itself to the Apple DOS 3.3 operating system and spread via floppy disk.
- Brain: created in 1986 in Pakistan, reportedly to detect piracy of the software that was written.
- WinVir: it was discovered in 1992. The virus didn´t contain any Windows API calls, instead relying on DOS interrups.
- VLAD Virus: created by Australian hackers in 1996, it was the first virus to target Windows 95.
- Win32.Cabanas: In 1997, this encrypted, memory- resident stealth virus was the first that targeted Windows NT.
Latest viruses:
Zeus: it´s a Trojan that steals bank accounts. The users are infected by spam ads that offer discount merchandise, counterfeit clothing design or some similar scams that are on the social network Facebook.
MiniDuke: it´s a Trojan that exploits a vulnerability found in Adobe applications since late 2012. The computers are infected by dowloading a PDF that contains information about Human Rights.
Shamoon: Shamoon is a new virus that deletes the contents of the computer and doesn´t allow the same restarts, it´s propagated through e-mails into an executable file, removable drives and share networks.
SabPub: it explodes a vulnerability in Java to infect their victims. It´s distributed by using a Word document that take advantege of the CVE-2009- 0563 vulnerability in Office for Mac.
Win32/Dorkbot: it´s spread through messages on Facebook chats and Windows Live Messenger.
