Tools and techniques to protect information from viruses

     Computer viruses are called small-size program that can attach itself to other programs and perform unwanted actions to the user. The life cycle of a virus consists of: Introduction. Incubation period. Reproduction. Destruction. The signs of the emergence of the virus are: Slowing of the PC. You can not boot the OS. Freezes or crashes frequently the PC. Reducing the amount of free RAM. The destruction of the file structure.
     Classification of computer viruses on the principles of: Habitat. OS. Features of the algorithm. Destructive capabilities. Depending on the habitat viruses are divided into: boot, file, system, network, macro viruses, and their combination. Boot - the boot sector of the disk. File - embedded in file execution. System - occur in the module system. Networking - use network protocols and e-mail. Macro viruses infect documents, spreadsheets and presentations. OS - Affected OS.

     The peculiarities of the algorithm is divided into: Residential - leave in the memory-resident portion of your PC, which then hooks OS appeal to other objects. Non-resident - use special techniques to hide their presence. Invisible Man - lead to overflow of main memory. Replicator - create copies that differ from the original. Program mutants - do not infect the operating memory and are active for a limited time. By destructive actions: Harmless. Non-hazardous. Dangerous. Destructive. Anti-virus protection.
     In general, PC antivirus system includes several components: scanner with graphical interface. Scanner with a command line interface. Resident caretaker. Mail guard. Scheduler. Update module. Virus scanner checks the media for viruses, detects and neutralizes viruses in computer memory, on disk, and in the email. Resident caretaker notifies the user when it detects infection or suspicious files. Mail guard inspects incoming and outgoing e-mail. Task Scheduler allows you to automate startup programs that make up the virus scan. The Updater is designed to receive the updates antivirus databases, new versions of software components. Computer virus written specifically, small-scale program that causes disruption of the normal performance of various user programs, corruption of files, create different interference of the PC. Computer virus can disrupt the entire computer, or operation of its operating system, disrupt the individual user programs.
     Antivirus: Norton, Kaspersky, Dr. WEB The basis of most anti-virus programs on the principle of searching virus signatures. Virus signature is a unique characteristic of the virus program, which gives the presence of the virus in the computer system. Usually in the anti-virus software is regularly updated database of virus signatures. Antivirus program scans the computer system by comparing and finding compliance with the signatures in the database. When it finds a match, it tries to calculate the detected virus.
     By the method of anti-virus programs are classified as: filters, reside in memory, as a resident, and intercept all requests to the operating system to perform additional actions, ie operations used for viruses to replicate and damage information and software resources in the computer, including reformatting the hard drive. Auditors, remember the initial state programs, folders, and system areas of the disk when the computer has not been infected with the virus and then periodically compare the current state of the source. In identifying inconsistencies message about this to the user. And doctor-detected and "treat" infected programs or disks "vykusyvaya" from the body of the virus infected programs. Detectors, can detect files infected by one or more well-known software developers viruses. Vaccine, they modify the program and drive so that it does not affect the program, but the virus from which the vaccine is produced, said they have already infected and is not embedded in them, etc.