Updated: Mar 17
The "zero day" exploit is an attack that exploits unknown vulnerabilities of an organization's hardware, firmware, or software that hackers previously discovered. Methods of discovery: Hackers may conduct their own research of zero day exploits.They may probe them (use of a program or inserted device to monitor or collect network activity data). Or, they may use to their advantage the time period while a relevant patch or anti-virus update is being developed to be made available to the public, after a zero day exploit is discovered.
Hackers may then access an organization's computer system, including their technical safeguards such as encryption, and access control, through such vulnerabilities. Those attacks are especially one of the most dangerous because of their novel nature: They do not resemble standard hacking attacks.