. https://blog.radware.com/security/2019/04/what-is-a-zero-day-attack/
blog article
Zero-day attacks are the latest, never-before-seen generation of attacks. They are not volumetric or detectable from a known application signature. Security systems and experts must react instantly to solve the new issues, that is, they have zero days to react. Advanced application-level attacks typically fit into this category. Two Distinct Phases. Probe and Learn: Hackers assess network defenses and probe for vulnerabilities, looking for different weaknesses and identifying the type of attacks that will potentially be effective. It’s like an archer who picks the best arrows to put in his quiver before battle. For example, a hacker may determine that a combination of encrypted attacks, attacks from a rotating IP address source, new low and slow attacks and headless browser attacks will be most effective. Optimize, Morph and Attack: Hackers launch the attack and then vary the attack vectors (or arrows from the quiver). In this case, hackers often understand that legacy DDoS mitigators need manual intervention to troubleshoot and mitigate a zero-day attack. So they attack the weakness of the legacy mitigator (multiple manual troubleshooting cycles to stop an attack) in addition to attacking the application vulnerabilities. READ MORE