A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the .. Računalni je virus mali softverski program koji se širi s jednog računala na drugo i ometa rad računala. Računalni virus može oštetiti ili izbrisati. Koliko virusi mogu biti opasni, govori i slučaj iz godine kada je kompjuterski virus Staksnet napravio haos u svetu i uspeo da ugrozi i iranski nuklearni.
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Secrets of Reverse Engineering. Viruses that utilize this technique are said to be in metamorphic code.
Many Windows users are running the same set of applications, enabling viruses to rapidly spread among Microsoft Windows systems by targeting the same exploits on large numbers of hosts. On page one of Dr Solomon’s Virus Encyclopaediathe virussi of viruses, even those that do nothing but reproduce, is thoroughly explained. Some viruses employ polymorphic code in a way that constrains the mutation rate of the virus significantly.
Most modern kompiuterski programs try to find virus-patterns inside ordinary programs by scanning them for so-called virus signatures. They generally target a specific type of email system Microsoft’s Outlook is the most commonly usedharvest email addresses from various sources, and may append copies of themselves to all email sent, or may generate email messages containing copies of themselves as attachments.
Inresearchers created and released a virus for Linux—known as ” Bliss “.
Even home computers were affected by viruses. See polymorphic code for technical detail on how such engines operate. Trojanac je zlonamjerni softverski program koji se krije unutar drugih programa. If a virus scanner finds such a pattern in a file, it will perform other checks to make sure that it has found the virus, and not merely a coincidental sequence in an innocent file, before it notifies the user that the file is infected.
Some viruses trick antivirus software by intercepting its requests to the Operating system OS. Retrieved 23 May Retrieved from ” https: However, not all viruses carry a destructive “payload” and attempt to hide themselves—the defining characteristic of viruses is that they are self-replicating computer programs which modify other software without user consent.
Crna Gora – Virsi. They can cause data lost and file corruption and need to be treated as soon as possible. Retrieved June 10, Archived from the original on September 6, Shareware and bootleg software were equally common vectors for viruses on BBSs.
For example, an executable may be created and named “picture. However, antivirus professionals do not accept the concept of “benevolent viruses”, as any desired function can be implemented without involving a virus automatic compression, kompjtuerski instance, is available under the Windows operating system at the choice of the user.
A virus may kompjuuterski send a web address link as an instant message to all the contacts e. Advanced Data Mining and Applications: Retrieved September 9, This page was last edited on 15 Decemberat Often a kompjuterwki will cause a system to “hang” or “freeze”, and a subsequent hard reboot will render a system restore point from the same day corrupted.
Payload activity might be noticeable e. Virus signatures are just strings of code that are used to identify individual viruses; for each virus, the antivirus designer tries to choose a unique signature string that will not be found in a legitimate program.
Are you sure you want to delete this value? Resident viruses overwrite interrupt handling code or other functionsand when the operating system attempts to access the target file or disk sector, the virus code intercepts the request and redirects the control flow to the replication module, infecting the target. Infection mechanism also called ‘infection vector’is how the virus spreads or propagates.
Different antivirus programs use different “signatures” to identify viruses.
Computer Viruses and Data Protection. Idite na web-mjesto Microsoft Security Essentials. This life cycle can be divided into four phases:.
Although most of these viruses did not have the ability to send infected email messagesthose viruses which did kompjutsrski advantage of the Microsoft Outlook Component Object Model COM interface. As software is often designed with security features to prevent unauthorized use of system resources, many viruses must exploit and manipulate security bugswhich are security defects in a system or application software, komppjuterski spread themselves and infect other computers.
This way, if data is lost through a virus, one can start again using the backup which will hopefully be recent. Computer virus Comparison of computer viruses Computer worm List of computer worms Timeline of computer viruses and worms.
Antivirus software does not change the underlying capability of hosts to transmit viruses. A second method to find viruses is to use a heuristic algorithm based on common virus behaviors.
Computer virus – Wikipedia
The virus places a copy of itself into other programs or into certain system areas on the disk. The Gammima virus, for kompjurerski, propagates via removable flash drives. The only reliable method to avoid “stealth” viruses kom;juterski to “reboot” from a medium that is known to be “clear”. Mark Russinovich November If the virus is encrypted with a different key for each infected file, the only part of the virus that remains constant is the decrypting module, which would for example be appended to the end.
This is one of the reasons that it is dangerous to open unexpected or suspicious attachments in e-mails. Press OK to Continue or Cancel to stay on the current page. This can slow down productivity for regular workers. The virus program is idle during this stage. Idite na web-mjesto Microsoft Safety Scanner. Archived PDF from the original on Guide to Computer Network Viursi. Macro viruses have become common since the mids.