Software-detectors (scanners) – designed to detect specific viruses. Based on the comparison of the characteristic (specific) sequence of bytes (signatures or masks of viruses) contained in the body of the virus, with the bytes of the checked programs. These programs need to be updated regularly as they quickly become obsolete and cannot detect new types of viruses. If the program is not recognized by the detector as infected, it does not mean that it is “healthy”. It could contain a virus that’s not in the detector’s database.
Programs-doctors (phages, disinfectants) –not only find files infected with the virus, but also treat them by removing the body of the virus program from the file. Polyphages – allow you to treat a large number of viruses. Detector programs are widespread, simultaneously performing the functions of doctor programs. Examples: AVP (author E. Kaspersky), Aidstest (D. Lozinsky), Doctor Web (I. Danilov).
Programs-auditors – analyze the current state of files and system areas of disks and compare it with the information stored earlier in one of the files of the auditor. This checks the status of the Boot sector, FAT, as well as the length of the files, their creation time, attributes, checksums (summation modulo 2 all bytes of the file). An example of such a program – Adin f (D. Bridge).
Filters (caretaker, monitor) is a memory-resident programs that inform the user about all the attempts of any programs to perform suspicious actions, and the user decides on the permission or prohibition of execution of these actions. Filters control the following operations: updating program files and system area of disks; disk formatting; resident placement of programs in RAM. An example is the Vsafe program. It is not able to neutralize the virus, you need to use phages.
Program-imunizator – recorded in the target program the specific characteristics of the virus so that the virus considers it to be already infected and therefore does not produce re-infection. These programmes are the least effective and obsolete.