The first computer viruses appeared immediately after the creation of computers. Programmers wrote them just for fun, they didn't do any harm. But modern computer viruses are created for completely different purposes and pose a serious threat.
All malware that exists today can be divided into two categories: viruses and Trojans. The first ones simply perform some negative or comic actions on the infected computer - for example, they can erase files or completely format the hard drive, turn off the computer, make the mouse inaccessible to the user, display a message, etc.
As a rule, the creators of viruses do not pursue selfish goals, most often such programs are written just for fun. But there are exceptions - for example, viruses that block the operation of the Windows operating system. The user sees a message in which he is asked to transfer some amount of money to a specific account, after which he will be sent an unlock code. Having encountered such a virus, you should remember the features of the message - in particular, the account or phone number (if it is proposed to top up the phone balance), then go from another computer to the websites of antivirus companies and look for the appropriate unblocker. But even if you fail to remove the virus, the worst consequences from it are formatting your PC's hard drive.
Trojans are the most dangerous. This type of malware is created to steal confidential human data. While the operation of a virus on a computer is usually clearly visible, the Trojan program tries to completely hide its presence. Its task is to collect the necessary information - for example, logins, passwords, bank card or online banking data, etc., and then discreetly transfer everything to the owner of the Trojan.
Quality Trojans are written by highly skilled programmers and can cost thousands of dollars. A well-designed Trojan is absolutely invisible; no anti-virus program can detect it - until the data about the Trojan gets into the anti-virus databases. Modern spyware can easily bypass firewalls. Having done their dirty deed, many Trojans self-destruct, leaving no traces behind. You can only find out that your computer has been infected with a Trojan after your bank card money has disappeared, or mailboxes, admin panels of your websites, etc. have been hacked.
There is also such a class of viruses as backdoors. By infecting your computer, a virus creates a loophole through which a hacker gains full access to the machine. He can view and copy information from disks, delete or add something. A hacker can use your computer to scan networks and hack into other computers to carry out attacks on servers. Thousands of compromised computers can be managed from one center, in this case a botnet is formed - a network of infected computers subordinate to one person.
Viruses and Trojans are a huge danger, so they are fought with in every possible way. The main problem is that the principles of construction and operation of the most common operating system today, Windows provide hackers with a lot of opportunities to create and deploy malware. OS developers are trying to patch up the gaps, but there are still too many of them. The Linux operating system is much more secure in this regard - it is no coincidence that many hackers use it. In any case, to protect against viruses and Trojans, the computer must have an up-to-date antivirus and firewall. You should also follow basic security rules - in particular, do not download or open suspicious files.
