Account takeover (ATO) fraud has become increasingly sophisticated, with attackers using advanced malware and tampering browsers to bypass front-end security measures, making client-side-only solutions inadequate. These fraudsters can steal valuable data, such as cookies and device details, and use browser tampering tools to mimic legitimate user environments, thereby evading basic fingerprinting and multi-factor authentication (MFA). To effectively combat these threats, a deeper server-side approach is essential, as it enables the validation and enrichment of client-side data and detection of replayed fingerprints. Companies like Fingerprint offer a multi-layered defense system that combines front-end and server-side intelligence, ensuring that identification events are genuine and untampered, thus providing robust protection against ATO attacks. Relying solely on free or open-source client-side fingerprinting tools can be risky for high-security accounts, as these solutions often fail to prevent sophisticated attacks, ultimately leading to potentially significant financial and reputational losses.