  The rapid growth and adoption of decentralized finance (DeFi) systems have
been accompanied by various threats, notably those emerging from
vulnerabilities in their intricate design. In our work, we introduce and define
an attack strategy termed as Role-Play Attack, in which the attacker acts as
multiple roles concurrently to exploit the DeFi system and cause substantial
financial losses. We provide a formal definition of this strategy and
demonstrate its potential impacts by revealing the total loss of \$435.1M
caused by 14 historical attacks with applying this pattern. Besides, we
mathematically analyzed the attacks with top 2 losses and retrofitted the
corresponding attack pattern by concrete execution, indicating that this
strategy could increase the potential profit for original attacks by \$3.34M
(51.4%) and \$3.76M (12.0%), respectively.
