| Anti-virus Software |
Website Links For Antivirus |
Information AboutAnti-virus Software |
| CATEGORIES ABOUT ANTIVIRUS SOFTWARE | |
| malware | |
| antivirus softwaremalware | |
| antivirus software | |
| security software | |
| computer viruses | |
|
Аntivirus software typically uses two different techniques to accomplish this:
Most commercial antivirus software uses both of these approaches, with an emphasis on the virus dictionary approach. Historically, the term antivirus has also been used for benign computer viruses that spread and combated malicious viruses. This was common on the Amiga computer platform. APPROACHES TO VIRUS DETECTION Virus dictionary approach In the virus dictionary approach, when the antivirus software examines 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) # 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 user's Hard Disk on a regular basis. Although the dictionary approach can effectively contain virus outbreaks in the right circumstances, virus authors have tried to stay a step ahead of such software by writing " Oligomorphic ", " Polymorphic " and more recently " Metamorphic " viruses, which encrypt parts of themselves or otherwise modify themselves as a method of disguise, so as to not match the virus's signature in the dictionary. Suspicious behavior approach The suspicious behavior approach, by contrast, doesn't attempt to identify known viruses, but instead monitors the behavior of all programs. If one program tries to write data to an executable program, for example, the antivirus software can flag this suspicious behavior, alert a user and ask what to do. Unlike the dictionary approach, the suspicious behavior approach therefore provides protection against brand-new viruses that do not yet exist in any virus dictionaries. However, it can also sound a large number of False Positive s, and users probably become desensitized to all the warnings. If the user clicks "Accept" on every such warning, then the antivirus software obviously gives no benefit to that user. This problem has worsened since 1997, since many more nonmalicious program designs came to modify other .exe files without regard to this false positive issue. Thus, most modern antivirus software uses this technique less and less. Other ways to detect viruses Some antivirus-software uses of 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. Some virus scanners can also warn a user if a file is likely to contain a virus based on the File Type . ISSUES OF CONCERN
LIST OF ANTIVIRUS SOFTWARE AND COMPANIES For corporate market
Commercial and shareware
Freeware This section includes usable free-of-charge versions of commercial software.
GPL software
Unclassified ''TODO: Classify the following: TESTING ORGANIZATIONS These organizations provide testing of virus scanning and related programs.
EXTERNAL LINKS
|
|
|