Are Magic Links Secure: A Technical Deep Dive Into Email Based Authentication

This technical article evaluates the security of email-based 'magic link' authentication: it presents a threat model covering token generation, email transport, user device and mailbox compromise, catalogs common attack vectors (token guessing, mailbox phishing/OAuth grant phishing, SMTP interception, link prefetching), references real incidents and CVEs, and provides concrete engineering mitigations—cryptographically secure 128+ bit tokens, server-side single-use enforcement, short expiries (5–15 minutes), device binding, prefetch resistance, and step-up authentication for sensitive operations.