Anti-Virusunlike other malicious programs such as spyware, worms, adware, rootkits, phishing and Trojan horses, viruses are computer programs that have the uncanny capability of propagating themselves to infect various system files and they can be transmitted via networks, the Internet, email, Instant Messaging, file sharing channels as well as removable media such as floppy disks, CDs, DVDs or USBs. Some computer viral infections display symptoms that will eventually be noticed by most computer users. However, the vast majority of computer viruses are surreptitious and cause havoc that goes undetected long enough for the damage to be irreversible. Those are the reasons that antivirus software products are so crucially important.
Antivirus software programs were originally created to combat the computer viruses that began to spread in the 1980s. Today's more sophisticated antivirus software programs are more prolific and, therefore, able to identify and remove viruses along with all other harmful malware. Upon finding any malware, the antivirus software programs will quarantine or encrypt the infected files to render them inaccessible or ineffective; they will attempt to repair the files by removing the malware but that cannot always be accomplished successfully; or they will delete the infected files entirely off the system.
The antivirus software programs are numerous and they all utilize one or more of the following three key methods for identifying malware: The most frequently used is the signature based detection method. This method breaks files down to little segments and compares contents of each of these segments against a dictionary of virus signatures which is, in essence, a listing of known virus codes. This method is somewhat limited as it can run its comparison only against known viruses and therefore will be unable to detect any of the new ones. Antivirus software that relies on the signature based detection method requires frequent updates to its virus signature dictionary and it is set up to examine all files when the computer's operating system creates, opens, closes or emails them.
The malicious activity detection method monitors the behavior of all programs and in that way provides protection against new viruses. Any suspicious behavior is reported to the computer used to decide how to proceed – to reject or to accept. The heuristic based detection method is utilized by the higher end and most advanced antivirus software and it is intended for identifying new and yet unknown viruses.
To accomplish its task the antivirus software that uses the heuristic – based detection method utilized one of two techniques: a) File analysis – it analyzes files containing suspicious and virus-like instructions which can significantly slow the computer down; or b) File emulation – it runs programs in virtual environments, notes their actions and performances and then determines whether those programs are malicious or not.
Needless to say, the optimal antivirus softwareand the one which is most effective is that which utilizes a combination of several of the above mentioned methods. After all antivirus software, it's all about protection from anti-virus computer infiltration and maintaining ones security.