What is Antivirus software?
With the appearance of the Internet people have faced a lot of new possibilities. Access to a wide variety of new useful information, fast and comfy communication with your friends and brand new business opportunities are among them. Unfortunately, information has become not only available but also less protected from violators. Many viruses have been devised to ensure hackers access to personal data, deleting files and performing hacker attacks to other users' computers. Usage of Email, local area networks, information exchange via various media carriers like CD, DVD and USB-flash device increases the danger of infecting. To solve these problems developers have created the anti-virus software.
Anti-virus software is used to detect computer viruses and malicious software; clean files damaged by them and prevent infecting the files and operating system with viruses.
The main tasks of anti-virus software are real time or on demand scanning the programs and files, scanning the Internet traffic and Email, cleaning and recovering damaged files and protecting against attacks of unsafe web resources.
There is a great deal of malware with new malicious programs appearing almost every day. The most common virus types are file and download viruses, macro viruses, network worms and hacker programs. That's why it is so important not only to have some antivirus software but also provide its regular updates. Thus, leading software companies developing anti-virus programs get updated several times a day; and inbuilt updating program allows checking for updates and getting the latest program version via the Internet. In the whole anti-virus software are divided into 2 types: classic antiviruses and complex programs for protection against various threads. The programs of the first type include an antivirus program and sometimes an antispyware module. The second protects your computer from any kinds of threads while you are surfing the Internet. Classic antivirus protects your computer and cures from a virus it only if it has this virus signature. In their turn as to the way of accessing files these programs are divided into on access monitors diagnosing files on access to them and on demand scanners running on user's demand. Behavior blockers are also considered to be complex anti-viruses for they blocks any program performing suspicious actions.
Classic antiviruses detect viruses only on the basis of unique virus signatures stored in the antivirus databases. However, this method is not very efficient because of quick appearance of new viruses. More up-to-date complex anti-virus programs use intelligent methods of thread searching like, say, proactive protection (Heuristics). Proactive protection implies scanning for malware as to the actions they are performing, i.e. analyzing reading/burning operations, accessing libraries and system registry. Thus, such programs analyze not the software itself but the actions it takes.
The task of antivirus developers is rather difficult for they have to get at least one signature of a virus they want to remove. Many viruses are not principally new; they just imitate other viruses and have similar operation methods. To fight these threads so called heuristic analyzers were devised. With the help of them antiviruses can find similar virus versions known to them and informs users about a possible virus containing on their computers. This method considerably increases anti-virus software efficiency and reliability for only a very experienced programmer can create a brand new virus that is not detected by antiviruses.