A zero-day threat (also known as a zero-day exploit) is when a threat actor discovers a cybersecurity vulnerability that is not known to the software vendor. It is called a zero-day threat as once the vulnerability has been discovered; developers have “zero days” to create a fix for it.
This type of vulnerability is dangerous as it can be exploited immediately before anyone, including the software vendor, has had a chance to respond and create a patch/fix for it.
Characteristics of a Zero-Day Threat
- Unknown Vulnerability: The threat arises from a flaw in software that has not yet been recognized or discovered by the vendor. This lack of awareness results in there being no existing updates or patches to mitigate the risk.
- Exploitation Before Disclosure:Â Attackers who discover a zero-day vulnerability can exploit it for various purposes, including installing malware, exfiltrating data or gaining unauthorized access to networks and systems. If the vulnerability remains undiscovered, the threat actors have a significant window of opportunity to carry out an attack.
- Impact on Security: The exploitation of a zero-day threat can result in significant security and data breaches. As the threat is unknown, organizations do not become aware of any breaches or attacks until after they have already happened. This can lead to data loss, reputational damage, organizational disruption, and legal and financial implications.
Types of Zero-Day Threat
- Software Vulnerabilities: This is a common examples of a zero-day threat, where a flaw is found in widely used software applications. A real-life example of this is the Kaseya VSA attack, which resulted in more than 1,000 companies worldwide being infected with ransomware.
- Hardware Vulnerabilities:Â Although a less common occurrence, hardware components can also contain zero-day vulnerabilities. Flaws in the architecture of processors etc could allow attackers to bypass security defenses and access data.
- Web Application Vulnerabilities:Â An unpatched flaw could be exploited to gain access to sensitive information or to take control of a server. A recent example of this was the exploitation of the MOVEit vulnerability in 2023, which resulted in thousands of organizations worldwide suffering data breaches.
Challenges of Defending Against Zero-Day Threats
- Lack of Awareness:Â This most significant challenges linked to zero-day threats is that organization do not even know if/when they are vulnerable. Without information about suspected vulnerabilities, organizations cannot implement effective defenses.
- Difficult to Detect: Identifying zero-day threats requires certain tools. Traditional cybersecurity measures, such as antivirus, are less likely to identify novel threats. There is a need for more sophisticated tools that use behavior-based detection and threat intelligence to identify these new, evolved cyberthreats.
- Patch Development: Once a threat has been identified, it can take some time for a patch to be created and distributed by developers. Organization remain at risk during this development time.
Strategies to Mitigate Zero-Day Threats
- Behavioral Analysis: Using solutions that focus on behavioral analysis, instead of traditional known signatures, can help organization identify suspicious activity that may be the result of the exploitation of a zero-day vulnerability.
- Regular Updates and Patching:Â Organizations should recognize the importance of regular updates to all software and hardware in the fight against cyberthreats. Even though this may not eliminate the change of falling victim to the exploitation of a zero-day threat, it limits the opportunity of hackers using known threats to access networks and applications.
- Threat Intelligence:Â Threat intelligence has become an important tool in the cybersecurity industry. Collaboration and sharing threat intelligence and insights can help organizations stay informed about emerging vulnerabilities and potential zero-day threats.