A zero day vulnerability is a type of computer security vulnerability that is unknown to the parties responsible for patching or fixing the vulnerability. This means that the vulnerability has not yet been publicly disclosed and has not been patched, leaving it open to exploitation by cybercriminals.
Zero day vulnerabilities can occur in a variety of software, including operating systems, applications, and network infrastructure. They can be exploited through a variety of methods, such as sending a malicious email or visiting a compromised website. To protect against zero day vulnerabilities, it is important to keep all software and systems up to date with the latest patches and security updates.
WannaCry
One example of a zero day vulnerability that received significant media attention and was widely exploited is the WannaCry ransomware attack in May 2017. WannaCry was a strain of ransomware that exploited a zero day vulnerability in the Microsoft Windows operating system called EternalBlue. The vulnerability, which had not been publicly disclosed or patched at the time of the attack, allowed the ransomware to rapidly spread to vulnerable systems through a network worm.
The WannaCry attack was estimated to have affected more than 300,000 computers across 150 countries, with total damages ranging from hundreds of millions to billions of dollars. The attack caused widespread disruption, with many hospitals and other critical infrastructure being affected. The attack was eventually stopped through a combination of a kill switch being activated and the release of a patch to fix the EternalBlue vulnerability. However, the attack highlighted the potential consequences of zero day vulnerabilities and the importance of promptly patching such vulnerabilities.