Credential stuffing poses a significant threat to online security, as it exploits the common practice of password reuse across multiple accounts, leading to costly data breaches. This form of cyberattack involves the automated use of stolen usernames and passwords, often obtained from the dark web, to gain unauthorized access to user accounts across various websites. Despite a relatively low success rate of 0.1-0.2%, the sheer volume of attempts makes it a potent threat, with notable incidents affecting companies like Dunkin', Zoom, and The North Face. To combat credential stuffing, organizations are encouraged to implement multi-factor authentication, use security questions, employ CAPTCHA tests, block suspicious IP addresses, and leverage device fingerprinting. These measures, alongside more advanced techniques like blocking headless browsers and monitoring for leaked passwords, form a comprehensive defense strategy. The emphasis on robust credential stuffing prevention is crucial for protecting user data and maintaining business integrity in the face of escalating cybersecurity risks.