Free antivirus software listings and antivirus software reviews.
Antivirus 101
There are competing claims for the innovator of the first antivirus product. Perhaps the first publicly-known neutralization of a wild PC virus was performed by European Bernt Fix (also Bernd) in early 1987. Fix neutralized an infection of the Vienna virus. The first edition of Polish antivirus software mks_vir was released in 1987; the program was only available with a Polish interface. Autumn 1988 saw antivirus software Dr. Solomon's Anti-Virus Toolkit released by Briton Alan Solomon. By December 1990, the market had matured to the point of nineteen separate antivirus products being on sale including Norton AntiVirus and ViruScan from McAfee.
How antivirus software works
In the virus dictionary approach, when the antivirus software looks at a file, it refers to a dictionary of known viruses that the authors of the antivirus software have identified. If a piece of code in the file matches any virus identified in the dictionary, then the antivirus software can take one of the following actions:
- attempt to repair the file by removing the virus itself from the file
- quarantine the file (such that the file remains inaccessible to other programs and its virus can no longer spread), or
- delete the infected file.
To achieve consistent success in the medium and long term, the virus dictionary approach requires periodic (generally online) downloads of updated virus dictionary entries. As civically-minded and technically-inclined users identify new viruses "in the wild", they can send their infected files to the authors of antivirus software, who then include information about the new viruses in their dictionaries.
Dictionary-based antivirus software typically examines files when the computer's operating system creates, opens, closes, or e-mails them. In this way it can detect a known virus immediately upon receipt. Note too that a System Administrator can typically schedule the antivirus software to examine (scan) all files on the computer's hard disk on a regular basis.
Some antivirus software use other types of heuristic analysis. For example, it could try to emulate the beginning of the code of each new executable that the system invokes before transferring control to that executable. If the program seems to use self-modifying code or otherwise appears as a virus (if it immediately tries to find other executables, for example), one could assume that a virus has infected the executable. However, this method could result in a lot of false positives.
Yet another detection method involves using a sandbox. A sandbox emulates the operating system and runs the executable in this simulation. After the program has terminated, software analyzes the sandbox for any changes which might indicate a virus. Because of performance issues, this type of detection normally only takes place during on-demand scans. Also this method may fail as viruses can be nondeterministic and result in different actions or no actions at all done when run ?so it will be impossible to detect it from one run.
Some virus scanners can also warn a user if a file is likely to contain a virus based on the file type.
Featured Antivirus Software
Panda Antivirus 2008
Panda Security
Detects and deletes all types of viruses. Keeps your PC free from spyware.
The new Panda Antivirus 2008 is the easiest-to-use protection for your computer. Just install it and forget about all viruses, spyware and online fraud. And you hardly have to lift a finger, so you can chat, share photos and videos with friends, read your favorite blogs or simply surf the Web, with complete peace of mind. And it's so light, you won't even notice it.
Kaspersky Anti-Virus 7.0 - 50% discount
Kaspersky Lab
Kaspersky Anti-Virus 7.0 - 50% discount!
Kaspersky Anti-Virus provides classic anti-virus protection from all types of malicious programs. You can be sure that your computer and your data is safe as you work and surf the Internet. Includes antivirus and antispyware using their award-winning technology.
CA Anti-Virus 2008
Computer Associates
Comprehensive Virus Protection
If you're unprotected, viruses can invade through email, downloads, instant messages, and even web pages. From there, they can erase your files, damage your hard drive, and destroy the information you value most: photos, music, documents, and more. CA Anti-Virus provides comprehensive protection against viruses, worms and Trojan horse programs.
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