Ayatullah Khamenei’s view on the issue is:

Making a living off of haram acts such as selling pork, liquor, establishing or managing nightclubs, centers of corruption and gambling and drinking and the like, is impermissible and the money made from such is haram and one who receives money from it, doesn’t become owner of the money.[1]

Also, engaging in bank transactions in which there is interest is impermissible and if one does so, he has no right to receive any income for it.[2]

In response to the question: “Is it permissible to get income for working in other parts of the bank i.e. management, credit, accounting, etc.? Ayatullah Khamenei has replied: “Working in other sections of the bank in which aren't associated whatsoever with the haram transactions that take place there is permissible.”[3]

So to conclude, if one works in a place in which he knows the income he is receiving is in return for a haram act, such as haram interest related transactions, his income will definitely be haram. Also, if he works in other parts of the bank (other than the section dealing with interest related transactions), but knows that the income he receives comes from a haram means, such as those transactions, it will without a doubt be haram. On the other hand though, if he works in a part of where it has nothing to do with those haram transactions, or doesn’t know whether the income given to him is mixed with haram money or not, it will be halal.