Before you begin your fast journey into the world of computers, you should know that on the Internet, as elsewhere, there are people who are simply malicious. On the Internet they are called hackers or hackers. There are several types of hackers, but their goal is the same: to transfer the main function of computer software in their favor. They usually do this using malware or malware. There are several types of malware: computer viruses, worms, Trojan horses, etc. We are not talking about differences in the types of software, but about what we can do to protect ourselves from it or, in the worst case, get rid from it using Anti-Virus software.
First, let’s see how we risk infecting our computer: malware gets into the infected file, which we give permission to execute on our computer, not knowing about it. Unwanted programs usually slip into legitimate programs and execute their actions silently in the background, so it can be difficult to determine if we are really infected. Infected files can be transferred in several ways: downloaded from the Internet, transferred from a USB drive, copied from a CD or DVD, or, most often, downloaded from an email attachment. That is why we should be careful when checking our emails and know what virus and firewall is.
The first thing you need to do on your computer is to check whether it has antivirus software on it and, if so, to make sure it is up to date. Contrary to what its name suggests, antivirus software protects not only viruses, but all types of malware. Antivirus works the same way as a vaccine: it protects the system from invaders when it is active, but like a vaccine, it cannot protect everything.
If we conduct risky behavior, we cannot rely on antivirus software to protect us. What antivirus and why? When we buy a computer, a computer store may offer to buy antivirus software at the same time. This choice may be wise, but keep in mind that there are several free antivirus programs on the Internet. Their goal is to protect us from malware, but they have fewer features. It’s up to you to decide if you need everything that paid software offers. In any case, you need antivirus and firewall security.
Not all viruses behave the same: some viruses remain activated in memory until the computer shuts down, others remain there all the time while infected applications are active. Shutting down the computer or exiting an infected application deletes the virus from memory, but does not delete it from the infected file or disk. If the virus is in the system file, it is activated again when the computer restarts from this disk. If the virus is introduced into the application, it is activated the next time the application is launched. Just copy the infected file to your computer and then activate the virus code (for example, by launching an infected application, but also by opening an attachment in an email). It can also immediately destroy the entire hard drive or even replicate the messaging system and send a message to all elements of the address book with a copy as an attachment! In some cases, it is enough to open an email to activate the virus, then it will do the work for which it was programmed. Letters can contain all types of executable files. Viruses using the Microsoft VBScript programming language (which is an interpreted language integrated into Windows) are widespread.
How does he detect the presence of the virus? There is a category of virus detectors that work with a collection of signatures. The simplest viruses include a series of characteristic instructions specific to each, but perfectly identifiable and called their signatures. A directory can be created to list new viruses. Programs that use this method are called scanners. They give very few false positives, but they are naturally ineffective for polymorphic viruses, since they have the ability to change their appearance. The disadvantage of this method is the need to periodically update the directory. There is another method that has the advantage of not requiring updating. It is based on heuristic algorithms for detecting virus capabilities in specific sequences of instructions. The probability of false positives is higher than that of scanners, but the efficiency is constant. At least until the appearance of a new general form of attack.