What is a zero-day exploit?
In the realm of cyberattacks and computer security, a zero-day exploit is the most feared type of attack. A zero-day exploit is a type of cyberattack that takes advantage of a software vulnerability that the software vendor is not yet aware of. Consequently, the vendor has not had the opportunity to release a patch or an update that would fix the vulnerability. This gives the attacker an advantage over their target as the target has no chance of being prepared nor able to defend against the attack.
Zero-day exploits are called so because they occur on the very same day that the software vulnerability is discovered and are exploited immediately. This means that the target organization or individual has no time to prepare for the attack, let alone defend against it.
Historically, the term zero-day refers to the days between the discovery of the vulnerability and the release of the vendor's patch. Zero-day attacks were relatively rare until the 2000s when cyberattackers began using them more frequently.
So how does a zero-day exploit work?
When a developer discovers a vulnerability in software, they report it to the software vendor. These vulnerabilities may be discovered by researchers examining the code of software or through the use of automated security tools.
Once the software vendor gains knowledge of this vulnerability, they develop a patch or an update that addresses the issue. If an attacker gains knowledge of the vulnerability before the vendor, they may use it to their benefit to cause major damage to the target. The attacker would create malware or a malicious code that exploits the vulnerability. They then wait for the right moment to launch the attack most likely for financial gain.
Nowadays, zero-day exploit attacks are no longer the realm of governments and only the most sophisticated hackers can carry them out. They are now sold on the dark web, which means that less technical but malicious persons who can afford it, can purchase these exploits and execute attacks successfully.
Real-life examples of zero-day exploits
While zero-day exploits can be elusive and hard to detect, they can cause significant damages that take a lot of time and effort to remedy. There been several high-profile examples of zero-day attacks over the years, which include:
Stuxnet – One of the most famous zero-day attacks is the Stuxnet worm. It was designed to damage Iran's nuclear program. It managed to spread to computers across the globe and caused physical damage to the centrifuges in Iran's nuclear facilities.
WannaCry – This was a ransomware attack that used a vulnerability in Microsoft Windows to spread itself across networks. The attackers demanded a payment of $300 in bitcoins to restore an individual's files, and more than 300,000 computers were infected.
Equifax data breach – In 2017, Equifax, one of the largest credit bureaus in the US, announced a data breach that exposed the personal details of over 147 million Americans. The company suffered this attack through a vulnerability in their web application software that was exploited using a zero-day exploit.
How can you protect yourself against a zero-day attack?
As we’ve seen, zero-day attacks can be devastating, and in most cases, they are not the average hacker. When an attacker chooses to launch a zero-day attack, they would have conducted extensive research and know their target inside and out. Therefore, it’s essential to take proactive measures to reduce the risk of being exploited.
Limit software installation – It's always a good practice to only install software that is necessary to do your job; any additional software on your system creates more opportunities for vulnerabilities to exist.
Keep your software up to date – Regularly updating your software ensures that the latest patches are applied, and your systems are best prepared to protect against the most recent exploits discovered.
Virtualize applications – Virtualizing applications minimizes the attack footprint. Doing this makes it harder for attackers to gain entry, and any vulnerabilities will not give them access to the underlying operating system.
Use multi-factor authentication – Using multi-factor authentication ensures that hackers cannot gain access to your sensitive information even if they have your password through phishing or other means.
Conclusion
A zero-day exploit is undoubtedly the nightmare of any cybersecurity professional and organization. Attackers use them to gain an advantage over their targets and cause damage that can take years to remedy. While zero-day exploits can be severe, there are ways to reduce the risks of a successful attack. Proactive measures like keeping software up to date, implementing multi-factor authentication, and limiting software installation can go a long way in keeping your organization safe. Cybersecurity professionals must continue to monitor this threat in an ever-evolving world of cyberattacks and protect against these dreaded zero-day exploits.
