Computer virus

Computer virus: 

A computer virus, much like a flu virus, is designed to spread from host to host and has the ability to replicate itself. Similarly, in the same way that viruses cannot reproduce without a host cell, computer viruses cannot reproduce and spread without programming such as a file or document.

A computer virus is a program or piece of code designed to damage your computer by corrupting system files, wasting resources, destroying data or otherwise being a nuisance. Viruses are unique from other forms of malware in that they are self-replicating capable of copying themselves across files or other computers without a user's consent.

History of computer viruses:

The first computer virus to be discovered in the wild was "Elk Cloner," which infected Apple II operating systems through floppy disks and displayed a humorous message on infected computers. Elk Cloner, which was developed by 15-year-old Richard Skrenta in 1982, was designed as a prank but it demonstrated how a potentially malicious program could be installed in an Apple computer's memory and prevent users from removing the program. The term "computer virus" wasn't used until a year later. Fred Cohen, a graduate student at the University of California, wrote an academic paper titled "Computer Viruses -- Theory and Experiments" and credited his academic advisor and RSA Security co-founder Leonard Adleman with coining the phrase "computer virus" in 1983. Famous computer viruses Notable examples of early computer viruses include the "Brain" virus, which initially appeared in 1986 and is considered to be the first MS-DOS personal computer virus. Brain was a boot sector virus; it spread through infected floppy disk boot sectors and, once installed on a new PC, it would install itself to the system's memory and subsequently infect any new disks inserted into that PC. The "Jerusalem" virus, also known as the "Friday the 13th" virus, was discovered in 1987 and spread throughout Israel via floppy disks and email attachments. The DOS virus would infect a system and delete all files and programs when the system's calendar reached Friday the 13th. The Melissa virus, which first appeared in 1999, was distributed as an email attachment. If the infected systems had Microsoft Outlook, the virus would be sent to the first 50 people in an infected user's contact list. The "Melissa" virus also affected macros in Microsoft Word and disabled or lowered security protections in the program. The "Archiveus" Trojan, which debuted in 2006, was the first known case of a ransomware virus that used strong encryption to encrypt users' files and data. Archiveus targeted Windows systems, used RSA encryption algorithms (earlier versions of ransomware used weaker and easily defeated encryption technology) and demanded victims purchase products from an online pharmacy. The "Zeus" Trojan, one of the most well-known and widely spread viruses in history, first appeared in 2006 but has evolved over the years and continued to cause problems as new variants emerge. The Zeus Trojan was initially used to infect Windows systems and harvest banking credentials and account information from victims. The virus spread through phishing attacks, drive-by downloads and man-in-the-browser techniques to infect users. The Zeus malware kit was adapted by cybercriminals to include new functionality to evade antivirus programs as well as spawn new variants of the Trojan such as "ZeusVM," which uses steganography techniques to hide its data. "Cabir" virus is the first verified example of a mobile phone virus for the now defunct Nokia Symbian operating system. The virus was believed to be created by a group from the Czech Republic and Slovakia called 29A, who sent it to a number of security software companies, including Symantec in the United States and Kapersky Lab in Russia. Cabir is considered a proof-of-concept virus, because it proves that a virus can be written for mobile phones, something that was once doubted.

 How does a computer virus attack:

Once a virus has successfully attached to a program, file, or document, the virus will lie dormant until circumstances cause the computer or device to execute its code. In order for a virus to infect your computer, you have to run the infected program, which in turn causes the virus code to be executed. This means that a virus can remain dormant on your computer, without showing major sings or symptoms. However, once the virus infects your computer, the virus can infect other computers on the same network. Stealing passwords or data, logging keystrokes, corrupting files, spamming your email contacts, and even taking over your machine are just some of the devastating and irritating things a virus can do. While some viruses can be playful in intent and effect, others can have profound and damaging effects, such as erasing data or causing permanent damage to your hard disk, and worst yet, some are even design with financial gains in mind.

How to protect against computer viruses:

As you can see, just like a vicious flu virus, a computer virus is something that you want to avoid. The terms virus and malware are often used interchangeably; however, a virus is one of many types of malware, and only one aspect of the overall threat landscape. As a result, traditional antivirus software alone will not fully protect you from all threats. Instead, look into comprehensive security software like Norton Security. With patented technologies that work together to outsmart online threats, scanning your system for viruses, and running continuous automatic silent updates, Norton Security keeps you protected from existing, new, and even yet-to-be-invented threats. And if a virus slips through on our watch during your subscription period, Norton support experts will do everything they can to help fix problem at no additional cost. That’s the assurance and peace of mind you only get with our Norton Virus Protection Promise. No other free or paid security software service offers this kind of guarantee.