Zero day malware, likewise called zero hour malware or absolutely no day attacks, is a type of malware that takes advantage of a formerly unidentified software application vulnerability. Attackers who have the ability to exploit these vulnerabilities can get access to a system or network without any detection. This makes no day malware a severe hazard to businesses and people alike.
Traditional malware, on the other hand, is malware that is popular and has actually been around for a long time. https://zerogov.net/?p=846 Traditional malware can still be unsafe, it is not as tough or stealthy to detect as zero day malware.