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.
|Published (Last):||3 April 2005|
|PDF File Size:||16.48 Mb|
|ePub File Size:||13.33 Mb|
|Price:||Free* [*Free Regsitration Required]|
Although most of these kompjuetrski did not have the ability to send infected email messagesthose viruses which did take advantage of the Microsoft Outlook Component Object Model COM interface.
Infection mechanism also called ‘infection vector’is how the virus spreads or propagates.
Sprječavanje i uklanjanje virusa i drugog zlonamjernog softvera
An example of a virus that does this is CiaDoor. A macro virus or “document virus” is a virus that is written in a macro languageand embedded into these documents so that when users open the file, the virus code is executed, and can infect the user’s computer. That is, each infected file contains a different variant of the virus.
Primjerice, XP Security Agent InFred Cohen published a demonstration that there is no algorithm that can perfectly detect all possible viruses.
A memory-resident virus or simply “resident kkmpjuterski installs itself as part of the operating system when executed, after which it remains in RAM from the time the computer is booted up to when it is shut down. Archived from the original on September 7, The first, and by far the most common method of virus detection is using a list of virus signature definitions. And there’s a clear pattern here which suggests an analogy to an infectious disease process, spreading from one resort area to the next.
Retrieved June 21, Defending a computer against viruses kompjuterskii demand that a file system migrate towards detailed and explicit permission for every viruei of file access. Archived from the original on 14 December Jompjuterski such viruses can be removed by rebooting the computer, entering Windows ” safe mode ” with networking, and then using system tools or Microsoft Safety Scanner.
This can slow down productivity for regular workers. This life cycle can be divided into four phases:. Even home computers were affected by viruses.
Security software can then be used to check the dormant operating system files. A few years later, in FebruaryAustralian hackers from the virus-writing crew Kompjyterski created the Bizatch virus also known as “Boza” viruswhich was the first known virus to target Windows 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.
The virus will eventually be activated by the “trigger” which states which event will execute the virus, such as a date, the presence of another program or file, the capacity of the disk exceeding some limit or the user taking a certain action e. Archived from the original on 24 May If two macro viruses simultaneously viruusi a document, the combination of the two, if also self-replicating, can appear as a “mating” of the two and would likely be detected as a virus unique oompjuterski the “parents”.
Idite na web-mjesto Microsoft Security Essentials. Users must update their software regularly to patch security vulnerabilities “holes”. Computer Viruses and Data Protection. The disadvantage of this detection method is that users are only protected from viruses that are detected by signatures in their most recent virus kkmpjuterski update, and not protected from new viruses see ” zero-day attack “.
The original hard drive can then be reformatted and the OS and all programs installed from original media. Polymorphic code was the first technique that posed a serious threat to virus scanners. Not all viruses have this stage. If a user attempts to launch an infected program, the virus’ code may be executed simultaneously.
False positives can be disruptive, especially in a commercial environment, because it may lead to a company instructing staff not to use the company computer system kompjuteerski IT services has checked the system for viruses. Crna Gora – Srpski. COM filesdata files such as Microsoft Word documents or PDF filesor in the boot sector of the host’s hard drive or kompjuterwki combination of all of these.
Just like regular encrypted viruses, a polymorphic virus infects files with an encrypted copy of itself, which is decoded by a decryption module. Komppjuterski other projects Wikimedia Commons.
The interception can occur by code injection of the actual operating system files kompjuteraki would handle the read request. Retrieved 2 September South Africa – English. Many websites run by antivirus software companies provide free online virus scanning, with limited “cleaning” facilities after all, the purpose of the websites is to sell antivirus products and services.
Secunia PSI  is an example of software, free for personal use, that will check a PC for vulnerable out-of-date software, and attempt to update it. Since these would be symmetric keys, stored on the infected host, it is entirely possible to decrypt the final virus, but this is probably not required, since self-modifying code is such a rarity that it may be reason for virus scanners to at least “flag” the file as suspicious.
One method of evading signature detection is to use simple encryption to encipher encode the body of the virus, vriusi only the encryption module and a static cryptographic key in cleartext which does not change from one infection to the next. The work of von Neumann was later published as the “Theory of self-reproducing automata”.
Basic Concepts and Solved Exercises. Some websites—like Google subsidiary VirusTotal.
The triggering phase can be caused by a variety of system events, including a count of the number of times kompjutersik this copy of the virus has made copies of itself. In this case, a virus scanner cannot directly detect the virus using signatures, but it can still detect the decrypting module, which still makes indirect detection of the virus possible.
In his essay von Neumann described how a computer program could be designed to reproduce itself. Are you sure you want to delete this value? There are two common methods that an antivirus software application uses to detect viruses, as described in the antivirus software article.