What Does Zero Day Virus Mean?
A zero day virus is a malicious software program that is not documented prior to a given day. When the virus is officially recognized and identified by an organization in the anti-virus community, it becomes a zero day virus. Professionals use zero day as the benchmark for responding to a computer virus.
Techopedia Explains Zero Day Virus
A zero day virus has a particular application to the anti-virus industry. Anti-virus software makers work from specific key principles, including the need to protect their clients from as wide a range of viruses as possible, and to limit, as well as mitigate, cyberattacks. This is a very competitive metric within the industry, as business/government clients and individuals seek to obtain the best anti-virus protection for their networks.
One problem with a zero day virus is that because it is not previously documented, it does not have a signature. Signatures involve reviewing the method and coding of a virus to anticipate and protect systems against the virus. One method of working against zero day viruses is the heuristic anti-virus method, which, using experience-based analysis, looks at other factors besides a signature for a virus to try to predetermine what a system needs protection against and what might be a virus.