Best Antivirus

A computer virus is malicious software designed to spread to other computers by inserting herself into legitimate programs called "guests." It can more or less seriously damage the functions of the infected computer. It can spread through any medium of exchange of digital data such as computer networks and CD-ROMs, USB keys, etc.

Its name comes from an analogy with biological viruses because it has similarities in the way it is spread using the reproductive capability of the host cell. It assigns the term "computer virus" in computer and molecular biologist Leonard Adleman (Fred Cohen, Experiments with Computer Viruses, 1984). Computer viruses are not to be confused with computer worms, which are programs that can spread and replicate on their own without contaminating the host program. In a broad sense, is often used and misused the word virus to designate any form of malware.

The total number of malicious programs known to be about 95 000 according to Sophos (all types of malware combined). However, the actual number of viruses in circulation would not exceed a few thousand depending on the WildList Organization, every antivirus vendor with an interest in "inflating" the number of viruses it detects. The vast majority affects the Windows platform. Although they are extremely few, there are also virus-like systems Unix / Linux, but no outbreaks similar to that of the Windows virus has been detected in 2010. The rest is mainly aimed at operating systems that are distributed over the past few years, as the 27 viruses - none being dangerous - imposed Mac OS 9 and its predecessors (recorded by John Norstad, author of the antivirus Disinfectant ). Systems are least affected FreeBSD that focuses its development on security, as well as Netware and OS / 2 too few to provide a developer known viruses. Viruses are often subject to false alarms that the rumor spread, bulky freight.

Some of them, playing on the ignorance of computer users, they sometimes destroy parts of the operating system completely healthy. The first autonomous software had no purpose they have today. The very first software of this type were mere entertainment, a game between three data of Bell, Core War, created in 1970 in the laboratories of the company. For this game, each player writes a program, then loaded into RAM. The operating system, which has just been multitasking, in turn executes an instruction for each software. The goal of the game is to destroy the opposing programs while ensuring its own proliferation. The players do not obviously opposing the location of the program. The software is capable of copying itself, repair itself, to move themselves into different areas of memory and "attacking" the software by writing random opponent in other memory areas. The game ends after a set time or when a player sees all its programs inactive or destroyed. The winner is the one that has the largest number of active copies. This is exactly the principles of programming viruses.

In 1984, the magazine Scientific American presented a computer game design consisting of small programs that come into s'autoreproduisant fight and trying to inflict damage on opponents, thus setting the stage for future viruses. In 1986, the ARPANET was infected by Brain, virus renaming all boot disks system (C) Brain. The creators of this virus gave them their name, address and phone number because it was an advertisement for them.

The virus is a classic piece of program, often written in assembler, which fits into a normal program, most often at the end but also at the beginning or the middle. Each time the user runs the program "infected", it activates the virus the opportunity to get integrated into other executable programs. Moreover, when it contains a payload, it may, after a certain time (which can be very long) or a special event, perform a predetermined action. This action can range from a simple message harmless to the deterioration of some functions of the operating system or damage to files or even complete destruction of all data on the computer. One speaks in this case "logic bomb".A boot virus installs a boot sector of a boot device: hard drive (the main boot sector, the "master boot record, or that of a partition), floppy or whatever. It replaces a boot loader (or boot program or "bootloader") entered (by copying the original elsewhere) or created (on a disc or there was none) but does not modify a program like a normal virus, when it replaces an existing startup program, it acts like a virus "prepend" (which is inserted at the beginning), but the fact of infecting a virgin device of any software startup differs from classical virus, which never attacks to "nothing."
When discovered, the virus is assigned a name. This theory is consistent with the agreement signed in 1991 by members of Computer Best Antivirus Research Organization. This name is determined as follows:

- Prefix, mode of infection (macro viruses, trojan horses, worms...) or the operating system concerned;

- A word expressing its special or flaw that exploits (Swen is an anagram of News, an anagram of Admin Nimda, Sasser exploits a vulnerability LSASS );

- In a version number suffix (the viruses are often taken the form of variants with similarities to the original version). Unfortunately, the analytical laboratories of various antiviral publishers sometimes affect their own name to the virus they are working on, which makes it difficult to find information. Thus, for example, the Netsky virus in Alternative Q is called W32.Netsky.Q @ mm Symantec, Trend Micro WORM_NETSKY.Q, W32/Netsky.Q.worm at Panda and I-Worm.NetSky. r at Kaspersky. It is possible to search for a generic name given through specialized search engines, such as Virus Bulletin or Kevin Spicer. Virus on Linux. The Linux operating system, as well as the Unix operating systems and related, is usually fairly well protected against computer viruses. However, some viruses can potentially damage Linux systems are not secure.