polymorphic virus


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polymorphic virus

A virus that changes its binary signature each time it infects a new file. Using a random number generator, a unique key can be created to encrypt each virus download that self extracts and executes when opened. Without an identifiable pattern to match, the only way to discover a polymorphic virus is by its actions (see behavior detection). See self-extracting file.

Also called a "stealth virus," hundreds of thousands of polymorphic Windows viruses are discovered every day. The actual number of antivirus families that generate that many files is perhaps a few thousand. See virus and antivirus program.
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References in periodicals archive ?
A modification of the probe, increasing the melting temperature, restored detection of the polymorphic virus strains.
Because of the conservative culture of the region, Nemec says the main threat in the Middle East comes from the polymorphic virus.
* Polymorphic virus A virus that can change its byte pattern when it replicates, thereby avoiding detection by simple string-scanning techniques.

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