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Definition: zero-day exploit


A malware attack that takes place after it is discovered and before the vendor of the vulnerable software deploys a patch, typically to the OS or Web browser. When a vulnerability is discovered by a user, it may wind up on one or two blogs, and the news travels fast. If only the software vendor becomes aware of it, the tendency is to keep the problem under wraps until a patch has been created to fix it. However, in many cases, vendors announce the flaw because users can then steer clear of the infected website or be sure to avoid opening a certain email attachment. See exploit.