The bizarre symptom: Intuit's MacInTax (a program later replaced by TurboTax) was designed to let Mac users file their taxes. But the version for the 1994 tax season had another feature, discovered by one taxpayer: It allowed any customer with a little telecommunications knowledge to dial in to a computer where 60,000 tax returns sat unprotected. Once in, a user could view any return, make changes, or simply erase the return entirely.
"The bug: MacInTax was bundled with a debug utility intended to help customers diagnose modem problems. The utility dialed in to a server operated by an Intuit subcontractor. The utility used an account name and password that weren't encrypted or otherwise obscured, and that granted anyone who stumbled across them complete access to MacInTax users' data. Intuit called the glitch "an oversight"--no kidding!--and apologized. The company offered to pay any penalties suffered by anyone whose return encountered problems as a consequence."