Zero-day Virus

Zero-day Virus

A Zero day virus is a previously unknown computer virus or other malware for which specific antivirus software signatures are not yet available.

Traditionally, antivirus software relies upon signatures to identify malware. This can be very effective, but cannot defend against malware unless samples have already been obtained, signatures generated and updates distributed to users. Because of this, signature-based approaches are not effective against zero-day viruses.

Most modern antivirus software still use signatures, but also carry out other types of analysis.