Broken Authentication in Fintech Systems

Most fintech breaches don't start with sophisticated exploits. They start with a login that should have failed, but didn't. Authentication sounds simple: you prove who you are, and you get access. But in practice, it's one of the most consistently broken parts of financial software. Not because developers don't care, but because the attack surface is wider than most teams realize during the build phase. Think of it like a bank vault with a perfect door but a weak combination. The engineering looks solid until someone figures out the combination only has a thousand possible values. In payment apps and digital wallets, broken authentication shows up in familiar ways: No limit on login attempts Password reset flows that leak user existence Session tokens that never expire JWTs signed with a weak or hardcoded secret. Any one of these, in isolation, looks minor. Combined, they hand an attacker a reliable path to account takeover. On the technical side, the common failures are: Missing rate