What is a virus?
- A program that has the following three features:
- Reproduction: the ability to multiply your own code – Stealth
- Previously, enough memory would run out of programs at a time.
- Floppy and / or hard disks run out of disk space faster than expected.
- Unexplained bugs occur.
- Some programs may slow down or stop working.
- Files, directories seem e1 or created for no particular reason.
- The virus scanning software indicates a virus, etc.
- A computer program can only be considered a virus if it meets all three criteria. If you do not meet all of these conditions, we will call it a virus-related program.
- virus types
- File viruses: they can only reproduce by copying themselves inside a program file.
- Boot viruses: Enter yourself in one of the boot areas on a floppy or hard disk. They become infected when the machine starts from an infected disk.
- Macro viruses: Many programs used today, such as Word, Excel, allow their templates to contain macros. Macro viruses are thus self-triggered macros that are attached to such a document and reproduce and bind to other document files. Their main spread: with attachments of emails.
- Mail viruses: they spread via e-mail, using mail servers and mail clients to spread them. Most of the time they are spread with attached files, but nowadays they are hidden in the body of the mail as special characters, which force the mail program or mail server to perform a special task.
- Trojan horses: do not reproduce, but get into the machine and cause some malfunction, eg. PCs and slow down network traffic.
- Spyware viruses: they do no harm, but provide information about the machine and the network via the Internet.
- Worms “multiply” only, reducing the amount of free space on the storage and causing severe system failures.
Where do they come from, who write viruses?
- University research laboratories: purpose eg. research (viral psychology)
- Military research laboratories: target eg. the host computer
- Developers of the Terrorist Organizations program
- Byproducts of copy protection
- Programmers dissatisfied with their working conditions
Defend against them
- Observe precautions: eg. I do not insert a foreign floppy disk into my machine unless I have verified that it is clean; I put my own disk in a foreign machine only for read-only purposes; I will not open attachments of emails from unknown people.
- Antivirus programs: eg. F-PROT, TBAV, SYSDOKI, SCAN, MSAV, OHK, etc.
- They later clean the disk and files of viruses when they are run. We don’t really use them anymore.
- Virus monitoring programs: eg. Norton Antivirus, PC Cillin, Mc Caffee, CA, Virus Buster, Kaspersky, etc. These are the antivirus tools we use today. During the operation of the machine, they provide constant protection if a virus is detected and prevented from entering. If there is a possibility that a virus has been introduced to your computer in the past, you can also start a virus scan to check the contents of your entire machine.
- Antivirus and antivirus vendors, if they find a virus, will kill or delete the virus, or quarantine the virus until newer versions are made.