Messenger of Allah (blessings and peace of Allah be upon him) cursed the one who consumes riba and the one who pays it, the one who writes it down and the two who witness it, and he said: they are all the same. (Muslim)
The principle is that any job within bank that has connection with interest transactions will be impermissible otherwise it will be permissible I.e. security guard, cleaner etc, which has no connection with interest transactions. But as a caution it is better to avoid.