Called dynamic code obfuscation, the method is being used by attackers to place encrypted virus code onto victims' computers, wreaking havoc for antivirus vendors, said Yuval Ben-Itzhak, chief technology officer of Finjan. For example, if two people visit a malicious Web site at the same time, each person will get a different encrypted or obfuscated code, generated on the fly with a different set of function and parameter names. The dynamic obfuscation method makes virus signatures virtually useless since different encryption keys change the way malicious code will exist on a victim's machine.
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