If a forged card and the PIN are both obtained, every last yen in the account ends up withdrawn.

Literal

Forged card [and-と] PIN [subject-が] if-come-together-[ば], account [in-に] exist as-much-as [of-の] cash [subject-が] gets-withdrawn-[completive-てしまう].

Financial-crime topic. 揃う = 'to all come together, form a complete set' — used when multiple required elements are assembled. ~限り on a verbal clause means 'to the extent that X is the case'; ある限りの現金 is 'cash to the extent that it exists' = 'every last yen there is.' The ば conditional sets up the hypothetical, and the passive 引き出される + completive ~てしまう conveys both that the withdrawing is done to the account (not by it) and that the outcome is irreversible.