Working for a bank

In a banking institution the only income they do earn is through Riba. There is no other income generation process involved in a Bank's system. And it means, a bank is paying salaries and profits to all of its employees and partners through the generated income which is nothing but Riba. In that scenario, how can it be legal for an employee to receive such an income which he knows that is paid to him through Riba, and at the same time he knows that he is a part of the machinery where business is nothing but to generate Riba income. In my opinion it becomes totally invalid for a muslim to be associated with a banking institution. Am I right?