On May 7, 2024, Visa announced the Visa Account Attack Intelligence (VAAI) Score, a fraud tool that uses generative AI to detect “enumeration attacks” - the automated guessing of card numbers, expiry dates, and security codes by fraudsters testing stolen or fabricated credentials at scale.
According to Visa’s official announcement, the VAAI Score learns normal and abnormal transaction patterns and produces a real-time risk score in about 20 milliseconds, trained on more than 15 billion VisaNet transactions. Visa said the approach reduces the false-positive rate by about 85 percent compared with other risk models for this type of attack. Visa estimated that enumeration attacks drive roughly $1.1 billion in fraud losses each year and that about a third of enumerated accounts experience fraud within five days.