Case study of the vulnerability of OTP implemented in internet banking systems of South Korea

The security risk of internet banking has increased rapidly as internet banking services have become commonly used by the public. Among the various security methods, OTP (one time password) is known as one of the strongest methods for enforcing security, and it is now widely used in internet banking services. However, attack methods which can detour OTP have been developed that additional security for OTP is now needed. In this study, we discovered that a new kind of attack through OTP is theoretically possible through an analysis of the currently implemented OTP system and known attack methods. Based on our theory, we tested the new attack method on Korean internet banking services, and empirically proved that it could effectively detour around all of the currently implemented OTP security systems in Korea. To prevent this, we also suggested solutions based on the root cause analysis of the OTP vulnerabilities.